The 648R is a T47 (47mm x 1.0) right hand threaded standard guide for use when facing bottom bracket shells with the BFS-1 Bottom Bracket Facing Set and 690-XL Oversized Facer This guide is used on the non-drive or left side of the bike - this side of the bike drive uses a clockwise or right hand threading Tap Guide BFS-1 47mmx1 648RUPC/EAN/GTIN: 763477013446