Shimano Shimano BB-UN300 Bottom Bracket (British Thread)
A good quality bottom bracket for traditional chainsets
Super-accurate bearings for smooth operation and improved durability
Durable, hard-wearing sealed cartridge bottom bracket with square tapered spindle fitting
Maintenance-free sealed cartridge bearing assembly keeps out dirt, mud, and water for long bearing life
Fast and easy installation without adjustment
Narrow body allows clearance for cable routing under the bottom bracket.
Also recommend: Shimano UN74S cartridge bottom bracket cup installation tool