I have already ordered qty=10 Hitachi Microdrive of 4Gbyte each.
second-hand mechanical data deathtraps
Brand new!
I did experiments on second hands units, then I found a retailer that stocks goods of a particular legacy type for sale, giving him the exact P/N the additional note, ~ "please skip OEMs, and please check if units have no Apple logo on the back, because if they have, I do not want them".
Those OEM with the Apple logo on the back are listed at half price. There is a reason for this, now we know why