It is a really good piece of kit, but the bash guard doesn't correspond with all Shimano chain rings. The guide is really good, and the chain tensioner quietens down rowdy rides and gives piece of mind, however the chain here runs over rubber and plastic instead of a mini jockey wheel, replaceable yes, but I think a jockey wheel like on a derailleur would be better...a really decent device but double check your chain ring and be aware that you will need spares/replacement innards for the chain tensioner.