Eddie, correct, it's a small metal block were the release screws into. The block has 2 small screws that should attach it to the back of the shutter ring. I think (not 100% on that though) that the cable release block is a mechanical version, not like the pneumatic one on my 12" Velogstigmat Series II studio shutter... I tried fitting the pneumatic actuator onto the Series A lens, but it was the wrong size :-(