Question 1

Is there an activity flashing light ?

Accepted Answer

Slow blinking blue light.  It does not blink to indicate the speed of transfer.

Question 2

Listed as 100mb speed; if it's usb 3.0 it seems it should be rated at usb 3.0 speeds?

Accepted Answer

On the back of the package it says: 
write speeds as much as 100mb/s USB 3.0 required (to get that speed, it is backward compatible to USB 2.0 and it says read speeds up to 10X USB 2.0.

So hope that answers your question, I have not done much with it but test it out, to see if it works.  Just letting you know that isn't a mistake on the web page, unless they are also mistaken on the package.

Question 3

does it have write protection?

Accepted Answer

If you are looking for the equivalent of lock/unlock switch on SD card for this SanDisk Ultra flash drive, you will not find it on the flash drive. It provides a software called SecureAccess to create password protected folders.

Questions & Answers