Blackspire stinger chain tensioner single ringthis single ring chain tensioner is designed to reduce the chance of dropping the chain by adding tension to the chain an additional benefit is that shifting is also improved due to the increased chain stability featureslight weightworks with almost any bashringmolded rollerfits up to 40t chainringsintended for freeride and all mountain ridingweight 90gbuyblackspire componentsfrom chain reaction cycles the worlds largest online bike store