YOU ARE LOOKING AT A BRAND NEW HOBBS PRESSURE SWITCH FACTORY SET AT 4 PSI. PART # 76575-4 N/0. THESE ARE GENUINE HONEYWELL HOBBS SWITCHES, NOT AFTERMARKET OR " FOR HOBBS" SWITCHES. THEY ARE ADJUSTABLE FROM 1 PSI TO 10 PSI. IT HAS A WORKING PRESSURE OF 250 PSI. IT IS A NORMALLY OPEN SWITCH. THIS SWITCH MAY BE USED TO TURN SOMETHING ON AT A SET PRESSURE. IT HAS 2 SCREW TERMINALS AND THE THREADS ARE 1/8 X 27 NPT. SWITCH SHIPS IN BUBBLE ENVELOPE WITHOUT BOX TO KEEP SHIPPING COSTS DOWN. NEWEST MODEL! I WILL SET THE SWITCH TO YOUR DESIRED SETTING JUST LET ME KNOW WHEN YOU PURCHASE IT. CONTACT ME FOR SPECIAL PRICING ON LARGER ORDERS. THANKS FOR LOOKING