Product Description Technical Information:Application:RoadMaterial:7075-T6 aluminiumBolt Circle Diameter:130 mmTeeth:39, 53Thickness:3 mm (39-tooth), 5 mm (53-tooth)Technology:X-Glide™Technology:X-Glide™ SRAM's crank engineers have thrown the old standards overboard and developed a completely new chainring geometry. They have precision-matched chainrings of different sizes and reworked the places where the chain and chainring meet. By adjusting the teeth of the chainring to the chain link pins (instead of to the middle of the chainring) you get twice as many shifting possibilities. Models:blast black / 39 tooth: Teeth: 39Colour: blast blackManufacturer Number: 11.6218.000.001 falcon grey / 53 tooth: Teeth: 53Colour: falcon greyOther: Hidden BoltManufacturer Number: 11.6218.000.000Contents:1 x SRAM Red X-Glide™ Yaw chainring Manufacturer: SRAM LLC 1000 W. Fulton Market 4th Floor Chicago IL 60607 USA info@sram.com Distributor: SRAM Europe Sales and Services B.V. Paasbosweg 16 3862 ZS Nijkerk Netherlands info@sram.com