Square taper BB tool set (cotterless crank puller, cartridge BB bracket plug, socket for impact driver) - 3-piece set This is a tool set for forcibly removing a seized square taper BB using an impact driver. All items have been used four times. Below are descriptions of each item. Cotterless crank puller (center in the photo) - Purpose: Removing the crank from a square taper BB (Allen key required separately) - Manufacturer: Unknown - Condition: Almost undamaged Cartridge BB bracket plug (left in the photo) - Purpose: Attaching and detaching cartridge-type bottom brackets - Manufacturer: Grunge - Condition: Scratches on the teeth (no problem for use) * Marks remain from removing the BB The socket for the impact driver (right in the photo) is a 24mm hex socket that fits the plug. Purchased at a local home center. Almost undamaged. Cartridge BBs have shallow grooves where they contact the bracket plug, making the plug prone to slipping out. Using an impact driver to remove the BB is a last resort and can damage the BB. If this combination doesn't work, you may have to destroy the BB with a chisel and hammer.