II's will work in a TK-50 drive, but I've been told they will. A TK50 (CompacTape I, 95MB) can be read in any TK drive up to a TK86 (CompacTape III, 6GB). A TK70 (CompacTape II, 295MB) is also upward but not downward compatible. However, if you fully erase a TK70 with a degausser it will work in a TK50 drive, but from then on it looks like a TK50 tape in a TK70 drive too. Re uVAX 2000 tape drives, a TK50-F is the original drive but the SCSI controller in the tape needs an upgrade if you use it with any other SCSI controller, like a MicroVax 3100. The TK50-G model had the updated ROMs, so given a choice look for the G model instead. Jack Peacock