It is a Total Systems 020/030 accelerator, with an SE PDS connector. It can also be attached to older Macs by using a killy clip (which I don't have). I forget the exact name of this accelerator, but it says PCB #80042 on it. I'll see if I can find the box and manual later (I know I have them somewhere).
The angle is 90 degrees, with the RAM parallel to the accelerator board.