Park Tool's 692 Left-Hand Bottom Bracket Tap is a 1.370" x 24 TPI replacement tap for the BTS-1 Bottom Bracket Tap Set. This tap is used on the drive side (right side) of the bike. This side of the bottom bracket uses a counter-clockwise or left-hand thread. Note: It is very important to have sharp and accurate cutting tools for effective tapping and thread-chasing. Using an excessively worn or damaged tap can cause permanent damage to the frame and/or bottom bracket.