The CeramicSpeed Preload Ring is an internal O-ring that securely fits to a crank spindle without the need for glue. It features metal threads which ensure the perfect preloaded adjustment. It is also designed to help avoid the accumulation of dirt or mud. This ring is compatible with any SRAM DUB crank and bottom bracket combination. It comes with 1mm and 3mm spacers to properly match the outer diameter. The CeramicSpeed Preload Ring is a great way to get the most out of your SRAM DUB system.