The Park Tool BBT-135-12 Steel Bottom Bracket Tool is a heavy-duty workshop tool machined from precision 4140 steel for removal and installation of threaded bottom brackets with 12-notch tool fittings. The BBT-135-12 fits 12-notch fittings with a major diameter of 48-50mm and a minor diameter of 46.3mm, including Praxis Works M30 bottom brackets - a standard found across a wide range of contemporary road and gravel drivetrains. The extra-deep body handles extra-wide spindles, and low-profile walls at the engagement point seat into recessed lockrings that standard-depth tools miss. Three drive options - 3/8" drive, 1" hex, and 36mm wrench flats - handle even heavily seized cups, and integrated threads in the tool body accept the Park Tool BBT-RS Bottom Bracket Tool Retaining System or GPS-1 Guide Pins (each sold separately) for improved stability during service.Machined from 4140 steel for heavy-duty workshop useFits 12-notch threaded bottom bracket tool fittings with a major diameter of 48 50mm and a minor diameter of 46.3mmCompatible with Praxis Works M30 bottom bracketsExtra-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 flatsOuter diameter at point of engagement: 57.5mm (2.264")Internal clearance: 42mm (1.654") depth x 30.44mm (1.198") diameterIntegrated threads accept Park Tool BBT-RS or GPS-1 Guide Pins for added stability (each sold separately)Not rated for use with impact drivers Park Tool BBT-135-12 Steel Bottom Bracket Tool Bottom Bracket Tools UPC: 763477001849