The Park Tool BBT-79.3 Bottom Bracket Tool is a precision-engineered tool designed for installing and removing 12-notch external bottom bracket cups with a 45-47mm outer diameter, including SRAM DUB and other compatible systems. Made from hardened steel, it ensures durability and a precise fit, preventing damage to bottom bracket components. Ideal for home mechanics and professional workshops, the BBT-79.3 is essential for accurate and secure bottom bracket installation and maintenance