clamp cast iron m co.

This is a lot of cast iron clamps.
I do not know what they are for.
There are all sorts of letters and numbers on them.
Some of the markings- M- Co. 300 U.S.A. … MAX 8" 1P ….353 FER 19 and some others I cant read.
All the screws turn, no frozen bolts.
They are vintage and they have been used.
They do show some wear.
Most of the rust looks like surface rust.
This lot will sell as used.