Threadless top piece thathas a bezel setsyntheticblue opal gem that measures at 4mm with a curved bar across it like a planet or orbit. Fits all threadless posts. Made fromASTM F-136 titanium with a 316L stainless steel pin.Length is approximately 5mm. Top size: 5.5mm x 3.5mm. Sold individually (1pc, top only).