Yess Ert-B Tensioner Black Bottom Bracket Mount Etrb

This bottom bracket chain tensioner does what no other chain tensioner can do. By applying the spring tension around the chainring, it allows the rear drop out area to be simple, uncluttered and lighter. No more deraillers sticking out and getting caught in anything! This can be used with or without our current arsenal of tensioners.-at only 6oz, provides peace of mind that chain will not fall off and potentially cause serious injuries.

• At only 6oz, provides peace of mind that chain will not fall off and potentially cause serious injuries
• Adjustable from 38T to 48T chainrings
• Tucked behind chainring to provide the smallest profile and minimum collision potential
• Allows gear swaps without compromising axle location and brake pad repositioning
• Provides the right amount of tension which can be fully adjusted
• Eliminates tight and loose section in the chain as the interface between link and sprocket can wear out unevenly