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 anodised surface finish,Mud grooves in the tooth bed,Ultra stiff I-Beam cross section,Mud clearance and wear-proof profiling,104mm BCD..Weight:30t 40g,32t 42g,34t 46g,36t 50g,38t 54g.Specifications:Material 7075 T6 aluminium,Fitting 4 Arm,Speed 8-11 speed,BCD 104,Teeth 30, 32 , 34, 36 or 38T .