The Park Tool HCW-17 removes and installs externally-notched lockrings which are found on fixed-gear rear cogs single speed cassette hubs adjustable cup-and-cone bottom brackets and some mid-drive e-bike motor lockrings including Batang BBSH & BBS02. The HCW-17 features two hooks with different radii for a precise fit on a wide range of lockrings. Constructed from spring steel and nickel plated for a lifetime of use.Fixed-gear lockrings with an outside diameter of 41 to 44 mmSingle speed cassette hubs with externally-notched lockringsAdjustable cup-and-cone bottom bracketsFour-notch Bafang BBSH BBS02 mid-drive motor lockringsLength: 295 mm (11.6")