The 691 is a replacement tap for the BTS-1 Bottom Bracket Tap Set in the 1.370" x 24 TPI right hand threading standard. This tap 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".
NOTE: For sharpening services of cutting tools see Park Tool Sharpening Services. Always use cutting fluid such as Park Tool CF-2 when machining.