- Stoke on Trent, UK
That’s a strange one.
Looks like an actuator cylinder at the moving jaw end. One connection to it unless another is at the other side. Screw at the rear would indicate an adjustment for the actuating stroke.
Some UK manufacturers made pneumatic actuated vice where say a foot pedal operated an air solenoid which would actuate the moving jaw.
Bit like this post from 2015
Value. No idea but it’s very rare IMHO.