<If they are labeled "CompacTape", yes. I'm not sure if the CompacTape II <will work in a TK-50 drive, but I've been told they will. You can not us <Compact III's or IV's (not that you would want to even used they are VER <spendy). CompactTapeII is not usable as it's for tk70 and is different oxide. The II tapes are the same size though. TK50 tapes can be read in tk70 but not the reverse. <Oh, and they are light grey. of course. Allison