Entirely developed, designed and produced in Denmark by CeramicSpeed, the Oversized Pulley Wheel System for SRAM eTap is a technologic advance for the cycling industry.Matching the highest quality materials with a unique design, the OSPW System delivers lower friction and longer lifetime, improving your competitive advantage. Thanks to the OSPW System for SRAM eTap, the power savings start at 40%, and the CeramicSpeed Bearings inside guarantee a 3-5 times longer longevity compared to commonly used standard pulleys on the market. The watt savings with a CeramicSpeed OSPW System for SRAM eTap start at 1.6 watts.The OSPW system for SRAM eTap derailluers is compatible up to a 32 tooth cassette size and with both short cage & WiFli derailluer bodies. The product is for 11 speed eTap and is not compatible with 12 speed SRAM eTap AXS. If you have the updated 11 speed SRAM eTap derailleur featuring the orbit clutch, you will need the CeramicSpeed OSPW System for SRAM eTap AXS derailleurs found here. In The Box-Oversized Pulley Wheel System-CeramicSpeed Bearing Oil in 15 ml. dropper bottle-Sticker sheetIMPORTANT: When travelling, please remember to dismount your entire rear derailleur with an Allen key, as the OSPW System will not fit in most bike travel bags and could be damaged if left on.