The Resideo 123869A/B Copper Well Immersion Assembly is a durable and efficient component designed for use with temperature-sensing controls in hydronic heating systems. Featuring a 1.5" to 3" insertion depth, this copper well ensures accurate sensor placement and reliable temperature readings. Its high-quality copper construction provides excellent thermal conductivity and long-lasti... https://www.partshnc.com/123869ab-resideo-12-copperwell-15-insl-3-insr