A set of 4 seals and a syringe of our low friction grease. These are all the parts needed to perform a service once the bearings start showing sign of contamination. We recommend a bearing service at least once per year, or sooner if you notice the bearings are getting crunchy or do not spin as smoothly as they used to. This set will service any of our hybrid ceramic pulleys. Please download our service manual for the best practices in bearing service.