I am sorry, but that is the only picture posted. 
That flatcable does not look like a 50 pin SCSI-cable, so I assume the drive is not SCSI either. And as a beige G3 only has 50 pins SCSI on board, to which the internal floppy drive is nót connected, chances are about zero that this drive will be SCSI.
Anyway, assuming the drive is scsi, as the sellers says, can it be used under AmigaOS somehow?
If it is indeed SCSI (which I seriously doubt), it will most likely function on your Amiga.
I have connected all kinds of removable drives to my A1200, ranging from 44 MB to several GB. Zip, Jazz, Syquests, MO-drives. They all work without any problems.