Indeed, not to be picky, but T Zero did not make "this" arm sculpture (as in, the one pictured), they made "an" arm sculpture. Cool little sculpture, sure, but a wee bit disappointing with that kind of lead-in.
Technically, it's called a "watch crystal lift," but others have correctly pegged it's use, so I'm hardly the first. It doesn't look like a delicate instrument, but it kind of is.
Sorry, that LOOKS like a tire-thumper, but note the indentations on the metal sleeve. This is actually a relatively new training tool used by the Isreali Special Forces to teach their elite soldiers how to deflect bullets wearing Wonder Woman type bracelets. It's their latest effort to maintiain their reputation among the special forces community of their unparalleled and insane bad-assedness.
Miah is right, it is a snuff tin opener, specifically a Copenhagen opener (with "Copenhagen" printed on the back of the "pie" crust part). However, I prefer to think of it as part of a keyring finger trap. Sort of like a bear trap, but smaller and less useful. My first thought, though, was perhaps an evil little piece of camping gear--for when you don't have toilet paper.