Renthal Sprockets & Chain Kit - Grooved Front Countershaft Sprocket & Blue Twinring Rear Sprocket & R3 Chain. GROOVED FRONT COUNTERSHAFT SPROCKET. Renthal Front Chainwheels are simply the finest front chainwheel on the market today. Their Front Chainwheels feature a specially developed Nickel-Chrome-Molybdenum steel which is case hardened and core refined to give the ultimate combination of strength and hardness. Precision CNC Machined to extremely tight tolerances. Case hardened and core refined 655M13 Nickel-Chrome-Molybdenum alloy steel to give the ultimate combination of strength and hardness. Self-cleaning mud grooves between every tooth on both sides help prevent dirt build up. TWINRING REAR SPROCKET. Unique flat face design keeps weight to a minimum and means the TwinRing is as narrow as a regular chainwheel. Inner Ring is high strength Ultralight 7075 T6 Aluminum. Outer Ring is Electroless Nickel Coated steel. Outer is expanded at 200C and then fitted to inner, creating a permanent bond for the life of the sprocket. Precision CNC machined to extremely tight tolerances. Flat socket head screws add additional strength to the chainwheel during side impacts. Self-cleaning mud grooves between every tooth on both sides help prevent dirt build up. R3-3 - MX SRS O-RING CHAIN. A premium high strength sealed ring chain with excellent impact load resistance designed specifically to withstand the stress found in offroad applications where an o-ring chain is desired. The R3.3 chain has been upgraded to the R4 ranges' proven quad riveting manufacturing process. Nitrile Self Regulating Seals (SRSTM) retain a special vacuum injected grease around the critical pin and bush area, which extends the life of the chain. Average Tensile Strength: 7420 lbs. Number of Links: 120. Master Link included.