Shimano BB-UN300

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