I have maybe a dozen acquired at an auction decades ago for about a buck each. I've never used them all at once and I've seldom, if ever, used them to clamp a glue-up. That said, they are, no doubt, the most frequently used clamps in my shop. Any time I want something to hold still on a temporary basis I grab one or two of them, from temporary fences, holding things on the drill press, holding a workpiece down to the bench, creating stops for cuts, and a million other things. I'd hate to be without them. I find them fast, convenient, and secure (unlike, say, the popular pistol grip clamps).