My Passport and My BookThe pocket drive and the mains-powered desktop unit. The disk in either one is ordinary. The board in front of it is not: it encrypts on the way through, password set or not, and the key stays on the board. Send the whole unit, case and all.
Elements and EasystoreThe plainer cases, sold without WD's backup software. Some pass the disk straight through and some do not, and you cannot tell from outside which you have. Either way the rule holds: send the unit as it stands, not a bare disk.
Blue, Black, Red, PurpleWD name their internal drives by colour. Blue is the everyday desktop and laptop disk. Black is the quicker one. Red goes in NAS boxes, so it nearly always arrives as one of a set and the set has to be handled together. Purple is built for recorders that write all day, which is why it turns up full of footage nobody can play.
SMR, and what it costs youSome WD drives write in overlapping bands, so altering anything means rewriting the band around it. They are slower when healthy and far slower when they are not. Imaging one runs to days rather than hours, in short passes, and no fee buys speed. Once a band has been written over, what was there is gone.