Constructed from precision-machined 4140 steel, the BBT-147-12 is a heavy-duty tool for the removal and installation of selected threaded bottom brackets with 12-notch tool fittings, including Chris King® ThreadFit™ T47 and ThreadFit™ 30. The BBT-147-12 is designed to be compatible with any bottom bracket featuring the corresponding tool fitting, with an extra-deep body to accommodate extra-wide spindles and low-profile walls at the engagement point for recessed lockrings. The BBT-147-12 offers three tool engagement methods: a 3/8" drive, a 1" hex drive, and 36 mm wrench flats, allowing you to tackle even the most seized bottom bracket cups. For added stability, the BBT-147-12 features integrated threads for use with the Park Tool BBT-RS Bottom Bracket Tool Retention System or GPS-1 Guide Spindles (each sold separately).