Victorian Sheet Celluloid Perforate with black glass OME. Cl 1-1.2.1 . Large at 1-3/8″ diameter. Under the sheet celluloid is a pop-up (there is a cut-out in the sheet celluloid and the glass fits through to the top of the button) faceted and lustered black glass. This has a pad shank (special shank type for those who compete in the button world).