"DELTADYNE IS A MATCHED ASSEMBLY, PARTS MAY NOT BE PURCHASED SEPARATELY AND ARE NOT NECESSARILY INTERCHANGABLE. NON-RESETTABLE. ACTUATION PRESSURE: 24 PSID + OR - 3 PSI. SYSTEM PRESSURE: 100-120 PSI; PROOF: 250 PSI; BURST: 400 PSI. TEMPERATURE RANGE: -65 TO +300 DEGREES F. FLUID: LUBRICATING OIL(MIL-L-7808, MIL-L-23699). ONCE ACTUATED THE BUTTON REMAINS IN THE ACTUATED POSITION UNTIL THE INDICATOR IS INVERTED AND MANUALLY DEPRESSED. THERMAL LOCKOUT: A BIMETAL ELEMENT IS PROVIDED WHICH PREVENTS ACTUATION BELOW 125 DEGREES F, PERMITS ACTUATION ABOVE 155 DEGREES F. HAS A RED INDICATOR BUTTON , EXTENDS 3/16"" WHEN ACTUATED (ANNODIZED AND DYED RED) TOP SURFACE OF INDICATOR BUTTON TO BE CLEAR."