The park tool bbt 192 bottom bracket is used to remove and install external bearing crankset bottom brackets fits external bearing bottom brackets with 16 external notches and an outside diameter of approximately 44mm park tool bbt 192 bottom bracket features the bbt 192 is a heavy duty shop quality tool for installing and removing shimanoreg sramreg truvativreg race facereg fsareg and campagnoloreg 16 notch external bottom bracket cups with an outside diamete