ASCO SA11A Tri-Point Pressure Switch is a compact two‑component device that pairs a sensing transducer with a snap‑action switch to trigger a signal at a precise preset point. It offers a 1/2 in NPT process connection and an explosion‑proof, watertight enclosure for harsh environments, with an electrical rating of 125 VDC and up to 0.5 A. Documented configurations show a sensing bulb of 9.5 mm diameter about 4 in long, with transducer unit models such as QJ110A1; typical set points cited around 131°F, while alternate transducer sets report about 126°F, and the operating temperature range is 100–220°F.
