Ultimate chain retention. All conditions.The Renthal 1XR chainring tooth profiling ensures the highest level of chain retention, in all conditions. Alternating 1.8 / 3.5mm width teeth interlock with the chain for ultimate security, with no loss of efficiency. The reduced frontal profile of the 3.5mm wide teeth increases mud clearance for the inner chain plates and extends longevity. Durability of the hard wearing 7075 T6 aluminium construction is maximised with a hard anodised surface treatment and mud evacuation grooves in the tooth bed.Features:*Alternating 1.8 / 3.5mm width teeth. *CNC machined 7075 T6 Aluminum.*Hard anodized surface finish*Mud grooves in the tooth bed*Ultra stiff I-Beam cross section*Mud clearance and wear-proof profiling*104mm BCD.Sizes: 32, 34, 36 and 38tWeight: 32t 42g34t 46g36t 50g38t 54gFactory Jackson review: http://factoryjackson.com/2015/04/07/renthal-1xr-retainer-chainring-review/"Although it has been a while coming, Renthal's entrance to the narrow/wide retaining chain ring market is damned impressive. It's nice when companies take a step back to make a genuinely great product and now another great British company have cracked it again. Must be something in the water."The Renthal 1XR chain ring is an absolute no brainer. Highly recommended."Dirt Rag review: http://dirtragmag.com/trail-tested-renthal-1xr-narrowwide-chainring/"During an excessively muddy and snowy winter on the East Coast my Renthal ring saw plenty of thick muck and it never failed. Not once"."Renthal has created a winner with its 1XR ring: it has been working flawlessly".MBR Magazine Review:"It took a while but the 1XR is superb quality and great value. If it lasts as long as the non-narrow/wide Renthal SR4 ring, it could easily be the number one choice for UK conditions".