The Park Tool BBT-118 Steel Bottom Bracket / Lockring Tool is a heavy-duty bicycle workshop tool machined from 4140 steel for removal and installation of components with eight-notch tool fittings. Suited for mechanics working across Shimano Octalink external cup bottom brackets, ISIS Drive cups from Truvativ and Bontrager, and front chainring lockrings on Bosch Gen 3, Gen 4, and Gen 5 e-bike systems as well as Specialized Levo Brose systems, the BBT-118 covers a wide range of drivetrain and e-bike service tasks with a single tool. The extra-deep body accommodates extra-wide spindles, while low-profile walls at the point of engagement allow the tool to reach recessed lockrings that shallower tools cannot access. Three drive options - a 3/8" drive fitting, a 1" hex fitting, and 36mm wrench flats - give the mechanic multiple engagement methods for tackling seized components. Internal clearance measures 31.14mm depth by 22.48mm diameter, with a nominal inside diameter of 37.6mm and outside diameter of 42.7mm at the eight-notch engagement.Machined from 4140 steel for heavy-duty workshop useEight-notch tool fitting with a nominal inside diameter of 37.6mm and outside diameter of 42.7mmExtra-deep body accommodates extra-wide spindlesLow-profile walls at the point of engagement reach recessed lockringsThree drive options: 3/8" drive fitting, 1" hex fitting, and 36mm wrench flatsInternal clearance: 31.14mm (1.226") depth x 22.48mm (0.885") diameterCompatible with Bosch Gen 3, Gen 4, and Gen 5 e-bike chainring lockrings and Specialized Levo Brose systemsNot rated for use with impact drivers Park Tool BBT-118 Steel Bottom Bracket / Lockring Tool - 8 Notch Bottom Bracket Tools UPC: 763477001832