A. This is an oil disc exhaust screw dust cap and an oil filler nozzle rubber sleeve suitable for mountain bikes and road bicycles. It is also a maintenance part for XT calipers. The specification is that one set includes one of each different style, which can well fit the oil disc systems of various mountain bikes and road bicycles, as well as XT calipers. B. These dust caps and rubber sleeves can effectively prevent dust, debris, etc. from entering the oil disc exhaust screw and oil filler nozzle, reducing the impact of impurities on the normal performance and service life of the oil disc and ensuring the stability and reliability of the bicycle braking system. C. For users who need to maintain and repair bicycle oil discs, this is a practical accessory choice that can provide safer protection for cycling. D. Both ordinary cycling enthusiasts and professional bicycle repairers can use this product to improve the performance and user experience of bicycles.