Manufacturer Name: United Electric Product Number: J21K-232 OEM Part Number: J21K-232 Product Description: Spdt 0-25# Nema 4 Diff. # Sw. Weight:1.85lbs/839.15g The United Electric J21K-232 is a single pole, double throw differential pressure switch designed to provide precise control in HVAC systems. It works by measuring the difference in air pressure between two locations an... https://www.partshnc.com/j21k-232-united-electric-spdt-0-25-nema-4-diff-sw