Multi-Zone Pump Control Relay; Item Multi-Zone Pump Control Relay; Type 4-Zone; Applicable Standard UL 873, CSA C22.2, ETL (Canada and US); Overall Dimensions 8.15" Width x 2.72" Depth x 10.67" Height; Current Rating 20 Amp at 120 Volt AC (Combined Load); Input Supply Rating 120 Volt AC 60 Hertz (Input), 40 Volt Amp 24 Volt AC (Transformer); Temperature Rating 0 to 100 Deg F; Media Handled Water; Application Zoned Hydronic Heating System; Relay Type Sealed; Thermostat Output Current Rating 0.5 Amp; Material ABS Plastic Cover, Galvanized Steel Base; Number of Knockouts 12; Knockout Size 0.875"; Humidity Rating 90 Percent