Torch SCSI Board
This item has been on loan to me since at least February 2007 as that is the date of this picture. In fact I know I have had it a bit longer as it arrived around Christmas time, but whether it was Christmas 2006, or the previous Christmas, or even the one before that, I can't bring to mind.
This is a Torch SCSI Board, and I know that because it's printed on it. Exactly how it is operates it less clear. I've powered it up, and measured volts flying across its little chips as evidence that it does something, but I haven't got a Beeb to recognise a SCSI disc attached to the end of it. Possibly it needs software other than ADFS to drive it, or possibly it needs something else as well as a SCSI disc attaching to the 50-pin end of it.