Renthals 4X Chainring is a specially adapted SR4 chainring for use on 4X bikes to offer the legendary stiffness & longevity to even more riders. Individually designed & CNC machined by tooth size, every 4X chainring provides the maximum stiffness & lightest weight possible to maximise performance while an anodised finish boosts longevity & keeps the 4X Chainring looking fresh. Hard Anodised Hard anodising process hugely increase the longevity of the chainring. This durable surface not only resists wear, but also keeps your chainring looking fresh. Chain Compatibility Compatible with all modern 8, 9, 10 & 11 speed chains. CNC Machined Each Renthal Chainring is machined from high grade 7075 T6 Aluminium. This computer aided design allows Renthal to machine away all un-necessary material to maintain excellent strength with class leading weight. Crank Compatibility Special 23.8mm axle bore is supplied with adaptors for 19mm & 22mm axles to cover all crank fitment options. Description by Mark, Rutland Cycling Web Team.