it's a round piece of black glass, I guess I'm happy it didn't arrive broken or scratched. Having said that, it shipped in very flimsy cardboard with some thin styrofoam for protection. After opening I found that the turning mechanism had broken off. Instead of going through the travails of returning/replacing I cleaned up the contact surfaces and re-attached the turing ring with super glue. It works now as intended but having had the chance to study the turning ring, I have to say that it is a low quality one that turns with some friction and a little noise.