• Simple and reliable square taper bottom bracket
• Replaces both BB-UN26 and BB-UN55
• Sealed cartridge bearings
• Cr-Mo axle
• For bicycles equipped with a chain case, select BB-UN300-K
• For E-type front derailleur compatibility, choose BB-UN300-E
• Fixing bolts not included; Shimano FC-E6000 bolts suggested