Sof-Lex Pop-On Starter Kit (Ref. 1980) Finishing & polishing discs for polishing of composite, compomer, metal and ceramic Flexible polishing discs with aluminium oxide coating. Discs can be easily changed with the patented Pop-On mandrel system Contains: 120 x 3/8” and 120 x 1/2” Discs (Standard), Coarse, Medium, Fine, Super Fine and 1 RA Mandrel.