Sealed pressure switch, choose your ON/OFF psi. 5 Amp. 165/200 pressure switches are custom DIRTY AIR stainless steel sealed pressure switches. 140/175 switches are custom DIRTY AIR brass sealed pressure switches. Ultra reliable. DIRTY AIR fast-up rear and front+rear systems use the 165/200 switch. 1/8"NPT thread. Always use a relay between this pressure switch and compressor.