Hi, I agree with Ivan, that’s it’s a basic belt lacing tool, I have a multi-size one, in which you can close all the lacings at the same time, on any width of belt up to the maximum width of the tool.
You just load up the number of lacings needed for whatever width your belt is, and then just push the belt into the lacings, up to the block where the pin holds the lacings in.
Then swing the top down, and clout the striking section with a hammer, maybe a number of times, and the job is done.
Needles to say, I haven’t actually shown any belt, as I haven’t got any.
Regards Nick.