I really like it when people repurpose things. Like when they turn shipping containers into houses or whipped cream into bikinis. And although this piston looks kind of angry and dead in its skullified iteration, I still give metalworkers Matt Griggs and Bill Riggle kudos for their aesthetic application of an otherwise entirely utilitarian mechanism.
One side of the ring has a smooth piston face, and the other a--boo!--creepy, bumpy skull face. Each piece is hand carved in wax prior to casting in Argentium 935 Silver (or sterling silver or 99.99 fine silver at the buyer's request). Since a mold is not used during the forging process, no two rings will be identical.