The Waters Performance Maintenance Kit for the XEVO TQD and SQD2 (scroll) Mass Spectrometer contains all the Waters Quality Parts necessary to keep your instrument operating at peak performance on an annual basis. The Waters Performance Maintenance Kit includes the following parts: Source components, ESI probe components and vacuum pump components. This particular part number does not deliver a chemical kit which is required to complete the performance testing. The part number for the PM Kit with chemistry is part number 176002781.