Veethree pressure switches are small, robust and reliable units used for pressure monitoring in gases and liquids by switching when specified limit is exceeded. These are the preferred preferred pressure switches for automotive use, industrial machinery, agricultural equipment, construction, marine and off road applications where long-term performance under demanding conditions is required. Veethree p/n 780940 Factory Set Point: 4 PSI (+/- 1.5PSI) Circuitry: Dual Circuit Terminal: THREE (Close, Normally Open & Normally Close) Type of switch: Normally Open/Close Notes: the N.C. circuit is the primary reference circuit and the N.O. circuit is not adjusted. Thread: 1/8" NPT Contacts: Silver plated copper alloy Diaphragm: Polyamide Moving contact carrier: Beryllium copper Base: Zinc plated steel Operating pressure: 100psi Burst Pressure: 500psi This pressure switch is manufactured by Veethree but can be used as a replacement for Honeywell Hobbs 76579 Pressure Switch.