I have two that are fairly standard. One is a Phillips I think, I use a 3 ton press to put it on. It is the standard Oval that many have shown already. The other one I have is a small oval, about 3/4 inch wide that I got off ebay, from a guy with a parrot in his logo. It is really nice and is good for throwing a very discrete mark on. Frankly, if I had that one to do again, I might consider getting
a 1", the 3/4" really is pretty small. It is plastic but the impression is great, and a normal tooling hammer will put it on. The plastic is supposed to last a very long time, and it was something like 25 bucks. I'm out of the shop for the summer, so I don't have access to the stamps, but I may be able to find something that has them on it.