The Waters Performance Maintenance Kit for the 7725i Rheodyne injector contains all the Waters Quality Parts necessary to keep your 7725i Rheodyne injector operating at peak performance. The kit also contains a detailed maintenance protocol, including calibration and diagnostic tools to ensure proper installation and function. The Waters Performance Maintenance Kit for the 7725i injector includes the following parts: One rotor, one rotor seal, and two allen wrenches.