The longer of DiMarzio's two black mounting ring screws, at 17 mm (roughly 11/16 inch). Humbucker rings are held down by four countersunk Phillips screws into the body, and the taller bridge-position ring on a Les Paul-style guitar generally needs this length to bite properly, where the low neck ring gets by with the 13 mm version. Black finish matches black rings, black covers and black pickup screws, so a replacement disappears into the guitar. DiMarzio part GP971B.