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Item#: N82E16835103179

Cooler Master Seidon 120M - All-In-One CPU Liquid Water Cooling System with 120mm Radiator and Fan

  • 600 - 2400 RPM (PWM) +/- 10%
  • 19.17 - 86.15 CFM +/- 10%
  • Fan Noise 19 - 40 dBA

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  • Overview
  • Specifications
  • Warranty & Returns
  • Reviews

Cooler Master Seidon 120M Liquid CPU Cooler

The Seidon 120M is Cooler Master’s latest, incredibly compact watercooling kit that aims to bring watercooling to the masses. It fits in virtually every case, is compatible with every available Intel and AMD platform, and as easy to install as a heatsink. It comes factory filled, sealed and tested with a two year zero maintenance guarantee. Thanks to a 120mm PWM fan with a wide RPM range Seidon can operate silently or unleash a powerful cooling storm at your command.

Utilizes a micro-channel design to maximize surface contact area to quickly pull heat away from your processor.
A reassuring blue LED indicator light shines brightly when the pump is powered and running properly.
Supports the latest sockets from Intel and AMD

- Intel LGA 2011/1366/1156/1155/1150/775

- AMD Socket FM2/FM1/AM3+/AM3/AM2
Guaranteed for maintenance-free operation for years to come without the need to refill coolant.

Technical Specs:

Model RL-S12M-24PK-R1
CPU Socket Intel LGA 2011 / 1366 / 1156 / 1155 / 1150 / 775

AMD Socket FM1 / AM3+ / AM3 / AM2
Main System Dimension Ø 70 x 27mm (Ø 2.75 x 1.1 inch)
Radiator Dimensions 150.3 x 118 x 27mm (5.9 x 4.6 x 1.1 inch)
Radiator Material Aluminum
Fan Dimension 120 x 120 x 25 mm (4.7 x 4.7 x 1 in)
Fan Speed 600~2400 RPM (PWM) ± 10%
Fan Airflow 19.17 ~ 86.15 CFM ± 10%
Fan Air Pressure 0.31 ~ 4.16 mm H2O ± 10%
Fan Life Expectancy 40,000 hours
Fan Noise Level (dB-A) 19 ~ 40 dBA
Fan Bearing Type Rifle bearing
Fan Connector 4-Pin
Fan Rated Voltage 12 VDC
Fan Rated Current 0.3A
Fan Power Consumption 3.6W
Pump Life Expectancy 70,000 hrs
Pump Noise Level 17dBA
Pump Connector 3-Pin
Pump Rated Voltage 12 VDC
Pump Load Current 0.15A
Pump Power Consumption 1.8W
Warranty 2 years
UPC Code 884102018930


  • newegg Superior cooling performance The COOLER MASTER RL-S12M-24PK-R1 features a waterblock machined out of a single block of copper for the best possible heat transfer. Precision machined Micro Channels maximize the water contact surface to quickly dissipate heat. Plus, its compact 120mm aluminum radiator fits in virtually any case, internal or external to satisfy various needs.
  • newegg Speed control for low noise Fin design is optimized for minimum air restriction to reduce fan speed and noise. 120mm PWM fan with a wide RPM range fines tune and balances fan noise and performance.

Learn more about the Cooler Master RL-S12M-24PK-R2

Warranty, Returns, And Additional Information
  • Warranty
  • Limited Warranty period (parts): 2 years
  • Limited Warranty period (labor): 2 years
  • Read full details

Customer Reviews of the Cooler Master RL-S12M-24PK-R2

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  • Jonathan B.
  • 1/29/2016 3:51:18 PM
  • Ownership: more than 1 year
  • Verified Owner

2 out of 5 eggsIt great for a year ... Then Died

Pros: It worked great for a year

Cons: Only latest a year.

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  • kevin m.
  • 1/27/2016 8:22:47 PM
  • Ownership: 1 month to 1 year
  • Verified Owner

5 out of 5 eggsGreat Product!

Pros: bought it back in september 2015. i have had zero issues.

Cons: none

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  • Michael W.
  • 1/19/2016 10:01:23 PM
  • Ownership: more than 1 year
  • Verified Owner

4 out of 5 eggsNoisy, wrong screws supplied.

Pros: Simple design. It works will, it does lower temperatures significantly. For the money a decent product. This is an introductory product for liquid cooling exploration.

Cons: The supplied fan needs to be much quieter, I had to replace it with a Noctua. I though these things were quieter. It is quieter than my old Zalman 9700 but that was almost 10 year old technology.
The supplied screws for mounting the fan and radiator to the case seemed wrong. There was 8 for this purpose though only 4 were needed. I was assuming that it was 2 sets of slightly different lengths (for slightly thicker cases or something). I was wrong they were 8 identical screws. The screws are designed to fit through the outer case through the fan and into the radiator. they cannot be too long since that would bore into the fins of the radiator. A specific length is necessary. I was mounting this into a Cooler Master (their own case) HAF and the screws were just shy of being able to thread into the radiator. I had to do a makeshift install. I had to purchase screws; unfortunately not the 1/8 inch longer that I needed but a 1/4 inch as that was what was available. so I had to also get rubber washers to make it all work. This should not have been necessary.

Other Thoughts: I had had this laying around for almost a year and a half before installing it. I just never got around to it before. I originally bought it because the newegg price was way to cheap not to get it and I had always wanted to try it out.
That being said it is a good foray into liquid cooling as a simple design..

Did you find this review helpful? Yes No

1 out of 5 eggsWorked great - not so much now.

Pros: - Great temp control while it worked
- Sorta quiet

Cons: - Louder than expected, although not that bad
- Started acting up within months
- Literally ZERO product support online, NO manuals for troubleshooting

Other Thoughts: I purchased the Seidon 120v; unfortunately, that product apparently no longer exists as NewEgg directs me to this page (the 120m) instead. This is the first and only product I have ever bought that has simply zero documentation - on the cooler master website there is NO DOCUMENTATION at all. My question was as simple as "what does it mean when the LED flashes" which is BASIC stuff - What the light means when its flashing/steady/whatever is probably the most generic support question there is. There is NOTHING on their website or anywhere else - even the "Product Manual" they let you download is USELESS! It's nothing but installation instructions.

My 120v worked great for a while, although it was a little loud. I noticed a strange sound coming from my tower today, about every second and a half. It is a steady "whirring" or pumping kind of sound, every other second, on the dot. The blue LED on the device (the portion that replaces the heatsink, directly over the CPU) has a flashing blue light now, which used to be steady blue (and had been since installation).

I am terrified to use my machine as I don't know if the flashing blue light means there is an error or something. I do not want to have another horror story where my system was fried because I had no cooling, and I don't know if that is the case right now because there is ZERO SUPPORT OR DOCUMENTATION! Cooler Master, what's up? Seriously, it takes FIVE MINUTES to write a BASIC support documentation for a product and toss it up online.

What does this flashing blue light mean? Where can I find ANY support for my 120v? The product page doesn't even exist anymore; when I click the item from my order history it goes here, so I don't know what to do. How do I handle this flashing blue LED + strange sound coming every other second?

As for the review - I was VERY happy with this product and would have gladly given it FULL stars before this happened. It was an incredible deal for the price and I was able to maintain VERY low temperatures even with pretty hardcore use. Unfortunately, I'm starting to feel that "you get what you pay for" after this.

Honestly, I don't know what to do at this point and am very upset that I cannot use my system unless I'm okay with risking permanent damage to it, simply because there is *zero* documentation about this (or ANY OTHER) issue!

0 out of 1 people found this review helpful. Did you? Yes No

  • Matthew F.
  • 12/31/2015 8:39:40 AM
  • Ownership: 1 month to 1 year
  • Verified Owner

4 out of 5 eggsGreat Product. Rad fan cable length could be longer.

Pros: Used with a new mini ATX build inside of a CM 130 Elite Case built about a month ago. Fits great; pretty quiet as well. I ran into a small issue that I cover below but I was able to solve it because of the case I was using.

Cons: One small issue I ran into was that the connector to bring power to the fan was too short to reach any of the fan headers on the motherboard that I was using (ASRock H97M-ITX). The fan headers are more towards the back of the motherboard; if the headers were closer to the front then I probably wouldn't have had an issue. Which is more an issue with the motherboard I suppose. If the cable was just a couple inches longer it would have been good.

Also the fan is 3-pin but has a 4-pin plug on the end; so it didn't fit a molex to 3 pin converter that I tried to extend the length with.

Other Thoughts: Luckily the 130 Elite's stock fan that is located in the front seems to be the same model as the one that comes with this product but with a longer 3-pin connector that was able to reach the fan header on the back of the motherboard. I'm not 100% if they are the same but I was happy that I didn't have to run out and buy an extender. I haven't had any problems with the product but I haven't really pushed it.

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  • Travis S.
  • 12/21/2015 12:15:19 PM
  • Ownership: 1 month to 1 year
  • Verified Owner

2 out of 5 eggsSemi great product

Pros: First of all i would like to say that for the price of this water cooler, it really out did itself, i could play GTA V on almost max settings and my processor would only get to about 31 degrees Celsius which is awesome!, it looks really cool as well, other than those two aspects there inst a whole lot more to say about this cooler.

Cons: Unfortunately in this situation cheaper inst better, yes it really cooled my cpu down a lot but the size of the fan on the radiator makes it so most medium sized cases will squeeze the fan when screwing your side panel on and the fan will hit the edges and not spin properly, also, i have only had my water cooler for about 5 months and it has completely died, even with those cons i would have still given this product a 4/5 if it was not for what happened next. after opening it on arrival(when i first received it) they put there serial number in a weird spot that most people would pull off without knowing it was the serial number, and to start the RMA process you have to register your product on their website with the serial number, and since i didn't have it i needed to contact customer support. the MAIN reason this product has a 2/5 is due to the customer service, it is noting short of a nightmare, i tried calling in to the number on their website, no matter what time of day, what option you select it always would say they are not able to answer at this time and to leave a message, i have left about 3 messages, never received a call back, in the meantime of trying to call i noticed they had a chat support, but it was ALWAYS offline, after checking a couple of days in a row it was finally online and i had to wait about 40 minutes to speak to an agent, who seemed to only want to get me off the chat, however it was not a hassle to get the RMA set it it was fairly easy in fact, but getting a hold of someone is a joke, the very next day i got back on to check the chat support and of course it was offline again, and their phone number still does not work. i sent my cooler back and according to ups it was delivered to the correct address and has been there for over a week and i have not received any kind of notice or update saying they have received it and started the RMA process, and of course, i am unable to contact them via phone and have to constantly be checking their website to see if their chat support is online.

Other Thoughts: With all that being said i would NOT recommend this product, and a side note, after installing this when i received it and seeing how awesome it was at the beginning i recommended this to my friend since it was so cheap and he has only had his for about 4 months and now it does not work, so now he is going to have to go through the hassle of getting in contact with their customer support.

1 out of 1 people found this review helpful. Did you? Yes No

  • Edward T.
  • 12/12/2015 10:48:59 AM
  • Ownership: 1 day to 1 week
  • Verified Owner

5 out of 5 eggsCooler Master Seidon 120M

Pros: Easy to install, in fact, it was easier than most aftermarket fans I've installed. Temps dropped from 39C to 25C at Idle and 57C to 33C under load.

Cons: None

Other Thoughts: Get one, well worth the money. My CPU max temp is 62C according to the AMD web site. Since my temps creeped close to that playing games and shot past 62C in under a minute using Prime95, I figured I'd try something new. I had never installed a water cooler and wanted to try so I shopped around a bit and this one seemed the most reasonably priced and easy to install so I grabbed one. Once installed, I ran Prime95 again and after about 5 minutes, the temps were bouncing between 39C and 40C. Granted, I need to run it longer to really test things out but given it took less than a minute with the stock cooler to shoot past 62C, I am very satisfied.

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  • Jose o.
  • 12/10/2015 8:07:13 PM
  • Ownership: 1 week to 1 month
  • Verified Owner

5 out of 5 eggs

Pros: For a AMD 8 cores no more than 30C run soul cool, Very Very silence. I gonna buy another if i see a good deal.

Cons: Is not a con but is not 1, 2, 3 not mount the cooling system.

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  • John B.
  • 12/5/2015 9:52:49 PM
  • Ownership: more than 1 year
  • Verified Owner

1 out of 5 eggsPump stopped working after 2 1/2 years

Pros: 2 Year Warranty
Works well when it worked
Backplace makes installation easy

Cons: Broke 2 1/2 years after purchase.
Must remove motherboard to install

Other Thoughts: For $70 it's not a good deal. I used this on my old q9400 Quad 2 Core and liked it because it was dead silent. 2 1/2 years after purchase it breaks and now I have to find an LGA 775 heat sink in the last month of 2015 that will cool a 4 core system. Not cool. Not cool at all.

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  • Anonymous
  • 11/27/2015 4:28:01 PM
  • Ownership: 1 month to 1 year
  • Verified Owner

4 out of 5 eggsGreat product, but problem when screwing

Pros: Overall the product keeps the CPU very cool even after being overclocked.

Cons: Unfortunately, as I was screwing it in it kept turning and I wasn't even trying to hard. Usually when screwing anything in it gets to the point where you have to put on a little force to tighten but in this case the screw just kept turning. For the 2 months I had this product it wasn't doing a lot of shaking even, though the screws weren't tightly in, but I prefer to have everything secured.

Other Thoughts: Very good cooler for anyone looking to replace a stock cooler just wish I able to have mine secured and not loose.

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Item#: N82E16835103179
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