Unique version of the legendary SR4 Chainring, this BMX Chainring from Renthal is designed to offer the excellent performance & long life of the SR4 ring in a BMX specific format. Computer aided, CNC machined design allows Renthal to shave every gram of un-necessary weight resulting in a high stiffness to weight ratio. Additional anodising treatment ensures the longevity of the BMX Chainring while boosting the look & style of your bike. 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 1/8 & 3/32 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.