Complete 9-Piece Air Compressor Pressure Switch Kit – Everything You Need in One Box.This comprehensive kit is designed as a direct replacement for most standard air compressors. Featuring a robust 4-port manifold pressure switch with a heavy-duty ABS cover and sensitive silver contacts, it provides reliable and sensitive pressure control (135-175 PSI). The set includes an accurate 2-inch dual-scale pressure gauge (MPa & PSI) for easy monitoring, a heavy-duty unloader relief valve, brass fittings, mounting hex wrench, and PTFE sealing tape. The "Unloader Valve" design makes it particularly suitable for two-stage compressors, ensuring safe, smooth operation. Perfect for DIY maintenance or upgrading your workshop air system! (Note: Please confirm the 4-port configuration fits your machine before purchase).