For quartering or quarter checking of drivers up to 1" outside diameter on 1/8" or 3mm axles. Permits quartering either right or left lead. Wheel is pressed onto axle while wheelset is still securely held in tool to avoid possibility of slippage. Can be used to compare quartering of existing drivers. Includes operating instructions and 2 index pins (crank pin substitutes). Requires .100" space on each side of gear to fit driver into tool.