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Cooler Master Atmos II Stealth 240 AIO Liquid CPU Cooler, Thicker Radiator, AMD AM5/AM4 & Intel LGA1851/1700 Support Cooler, 240mm, VRM Cooling Fan, Mobius 120P Fan Cybenetics AF Titanium SP Platinum
+ $10 off w/ promo code BNWF26, limited offer
- Dedicated VRM Cooling: Six-direction airflow helps cool motherboard power components, lowering VRM temperatures by up to 10.2C for improved stability.
- 29mm Thick Radiator: Thicker radiator design increases heat dissipation for lower CPU temperatures and stable cooling.
- Mobius 120P Fan: High static pressure and up to 190 CFM airflow push more air through the radiator while keeping operation quiet.
- Patented Dual-Chamber Pump: Up to 3,400 RPM helps move coolant directly to CPU hot spots for faster heat transfer and consistent cooling.
- Built To Last: Industrial-grade EPDM tubing helps reduce coolant loss over time.
- Advanced Copper Cold Plate: Ultra-thin fins and optimized microchannels help move heat away from the CPU faster for efficient cooling.
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Overview
Specs
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Warranty & Returns
Warranty, Returns, And Additional Information
Warranty
- Limited Warranty period (parts): 2 years
- Limited Warranty period (labor): 2 years
- Read full details
Return Policies
- Return for refund until: January 31, 2026
- Return for replacement until: January 31, 2026
- This item is covered by Newegg.com's Extended Holiday Return Policy.
- Read full return policy for details.
We want to ensure your holiday shopping this year is hassle-free. That’s why we’re automatically extending our return policies on almost every product! For purchases placed between November 1st, 2025 and December 31, 2025 you will have until January 31, 2026 to return your product.
Manufacturer Contact Info
- Manufacturer Product Page
- Manufacturer Website
- Support Phone: 1-888-624-5099
- Support Email: customersupport@coolermaster.com
- Support Website
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The Cooler Master Atmos II Stealth 240 is a 240mm AIO liquid CPU cooler for builders seeking CPU cooling with added motherboard VRM airflow; its six-direction VRM cooling is designed to lower VRM temperatures by up to 10.2°C. It supports AMD AM4/AM5 and Intel LGA 1150 through LGA 1851.
Recommended For
- Builders creating a clean, all-black PC who prefer a non-LED cooler and a pump design with fewer visible cables.
- PC builders with a case that supports a 240mm radiator who want liquid cooling plus airflow directed at motherboard VRM components.
- AM4, AM5, or supported Intel-socket upgraders who want one AIO platform compatible with their existing or planned CPU socket.
- Builders who want a 240mm AIO in a compact case and are willing to check radiator, fan, and pump-top clearance before buying.
Real-World Use Scenarios
- When building a gaming or home-creator PC with a case that supports a 240 mm radiator, users can add liquid CPU cooling without choosing a larger 360 mm unit; actual temperatures depend on the CPU, case airflow, and workload.
- For a compact PC build where a 240 mm radiator fits, this cooler offers a liquid-cooling option with a low-profile pump; check the case’s radiator and component clearances before buying.
- During CPU-heavy tasks such as compiling or rendering, the radiator and fans are intended to move heat away from the processor; results vary by CPU and settings, so users planning sustained overclocking should compare workload-specific tests.
- In a system where motherboard power components run warm, the included VRM fan module can direct airflow around those components; the practical temperature change depends on the motherboard and case airflow.
- For a clean, non-illuminated PC interior, the Stealth 240’s non-LED design avoids adding lighting; its pre-installed fans and quick-mount kit are intended to simplify installation.
Spec Summary
| Attribute | Value |
|---|---|
| Best For | Desktop CPU liquid cooling across supported AMD AM4/AM5 and Intel LGA 1150, 1151, 1155, 1156, 1200, 1700, and 1851 sockets |
| Socket And Platform Compatibility | Supports AMD AM4 and AM5, plus Intel LGA 1150, 1151, 1155, 1156, 1200, 1700, and 1851 |
| Pump | Pump speed of 3400 ± 300 RPM with maximum noise of 25 dBA |
| Radiator | Aluminum radiator measuring 277 mm, in a 240 mm cooler configuration |
| Fans And Airflow | Two 120 mm fan slots with 690–2500 RPM fan speed, Loop Dynamic bearings, a 7-pin connector, non-LED lighting, and airflow capacity of 190 CFM |
| Tubing | 350 mm tubing |
| Physical Design | Black finish; product weight is 3.06 lb |
| Model Identifiers | Cooler Master MasterLiquid AIO, part/model MLX-D24M-A24DK-R1 |