Park Tool BBT-29 Bottom Bracket Tool The BBT-29 is a double-ended bottom bracket wrench designed to fit 16-notch bearing cups with an outside diameter of 39mm (e. g. Shimano(R)Dura-Ace(R)9000/R9100 series and XTR(R)M9000 series) as well as 16-notch bearing cups with an outside diameter of 48. 5mm (e. g. FSA(R)Mega Evo(R)). Features Double sided bottom bracket tool Fits 16-notch bearing cups with outside diameter of 39mm or 48. 5mm Manufacturer's Part No: BBT-29 UPC: 763477000583 | Park Tool | Bbt-29 Bottom Bracket Tool Bbt-29