The TPMS rebuild kit contains all the components to rebuild the TPMS sensors valve. Replacement is recommended any time a TIRE/TPMS is serviced just like non TPMS rubber valve stems. These components include: hex nut, washer(s), nickel plated valve core, rubber sealing grommet, plastic sealed valve cap, and sometimes an entire metal valve stem or a rubber valve stem for TPMS.