Improved Pedaling Speed: The ceramic inner bearing reduces friction, leading to much smoother transmission and enhanced pedal performance. Ultralight and Durable: Constructed with CNC aluminum alloy, these jockey wheels offer maximum strength and durability while being ultralight. Wide Compatibility: Suitable for mountain bikes or road bikes and compatible with various rear speed derailleurs, compatible with SHIMANO and compatible with SRAM 8, 9, 10, 11, and 12-speed derailleurs. Easy Installation: Simple installation with an allen key, using the included accessory for compatibility with 4mm, 5mm, and 6mm derailleurs. Anodized surface prevents rust and corrosion. Set of 2 Jockey Wheels: The package includes a set of 2 13T jockey wheels, for componen.