Teac Tascam M-3500 M-3700 Jalco sockets in two variants

I have these listed elsewhere on the site , but people often search by model

These are from the M-3500/3700 mixers they are the ones that have a silver insert at the front not just plain black plastic

These sockets were used everywhere and have many variants.

Here I offer a two pin mono ( 1 socket pin on the left and right) and a  4 pin version ( 2 pins at the back the other 2 are further up left right) probably a stereo switch socket