I use these for welding and other clamping purposes in a machine shop.
I like the low profile head.
The clamping action is "straight in" and allows me to tighten the clamp without having the parts shift around, unlike the screw clamping type, which is slower and tends to wobble.
I used these clamps,many years ago, at work. They were the best clamps in the shop and I have been saving up for a long time, until I could afford to buy my own .