this is the latest version of one of the best selling hdds of seagate with encyrption feature which was not available is previous models and 3 years data protectionit says on description only usb 30 but any usb is backward compatible so dont worry if you have 20 porttransfer speed is stable and great enough so you can expect constant 120 mbs transfer rate with 30though i bought blue colour ill suggest you to go for black one cause it will look better931gb is usable out of 1tbi