The Shimano BB-UN300 Bottom Bracket is a quality square type bottom bracket for your standard chainset. Get improved durability and a smooth ride.

• Cartridge bearing square bottom bracket
• MTB standard structure
  
• Better chain line stability with chain line stabilizer
• Tourney A070 Series
• Shimano high quality/performance
• Adapter material: Aluminum
• Bottom Bracket Shell I.D.: 1.37
• Threaded BB shell width: 68mm
• BB/Frame Interface: English