KMC’s X12 chain features a comprehensive X-Bridge on the inner wall of all chain plates; the narrow design adapts precisely to the limited gear space while improving functionality, in spite of extreme cross chaining inherent to 1x drivetrains. Optimal asymmetrical chamfering is strategically placed on outer plates to avoid chain and cassette teeth interference. The upgraded bevel chamfering on the inside edges of all plates enable a smooth gear tooth insertion and an efficient interface between chain and cog. Riding safety and stability is drastically improved as a result.