These come from the 8TB MyBook External casings. The WD80EZAZ-11TDBA0 requires a 3.3v pin mod to cover the 3.3v reset pin or it wont work inside a desktop computer. It does NOT require this if you are using it on most server backplanes or if you are using a molex to sata power splitter as it doesn't have the 3.3v (orange) line. Interestingly enough, the drive doesn't have the 3 rows of screws on the belly to facilitate mount to a sled, but does have all the holes for mounts to a drive caddy for a server rack.