It holds 1 PX28 / LR44 6v Battery
I have available separately the OEM Canon strap that this was meant to work with
Original Equipment for Canon AE-1, AE-1 Program, A-1, AT-1, AV-1, AL-1 & F-1(new)
*not the early version of the F-1 though
Actual pictures of 1 of the items shown!
.
.