THIS WOLF TOOTH BOTTOM BRACKET TOOL IS PRECISION CNC MACHINED FOR INSTALLATION AND REMOVAL OF EXTERNAL CUP BOTTOM BRACKETS. HANDMADE IN THE USA AT WOLF TOOTH'S HQ IN MINNEAPOLIS. COMPATIBILITY BBS3916: 16 NOTCH BB SOCKET FOR 39MM DIAMETER NOTCH PATTERN, XTR/DURA ACE BBS4116: 16 NOTCH BB SOCKET FOR 41MM DIAMETER NOTCH PATTERN, ULTEGRA BBR60 BBS4416: 16 NOTCH BB SOCKET FOR 44MM DIAMETER NOTCH PATTERN, HOLLOWTECH II, CAMPAGNOLO, CHRIS KING, FSA MEGAEXO, HOPE, SRAM/TRUVATIV GXP, RACE FACE X-TYPE, SURLY, WHEELS, AND OTHERS BBS4612: 12 NOTCH BB SOCKET FOR 46MM DIAMETER NOTCH PATTERN, RACE FACE 30MM SPINDLE, TF47, SRAM DUB, RACEFACE CINCH, ZIPP VUMA, ROTOR BSA30, HAWK RACING BB3086 BBS4816: 16 NOTCH BB SOCKET FOR 48MM DIAMETER NOTCH PATTERN, FSA 386 MEGAEVO, WHEELS ® PF30