Install this Cab Heater in Large Construction Vehicles to Take Off the Chill warmer than air input. Alternator must produce 45 to 40 amps for enough power to operate heater. Mount low along floor under elevated seats on wheelwells or on the floor. Start vehicle before turning on heater. Operate heater and fan ONLY if engine is running. Installation required. Included wire optional dash mounted switch and universal mounting bracket. Back Seat Heat Model 4000 24 Volt Only Specifications Patent #4 9000 898 and 323 553 Voltage 24V DC Current 25 amp 24 VDC Power consumption 600W 2100 BTUs High temperature cut-out recycling limit switch Wire harness length 20 ft Universal mounting bracket Auxiliary control optional dashboard on/off switch Controls off fan only heat Adjustable thermostat Fan rating 102 CFM Assembled in USA Warranty 2 years Dimensions 5.25 in x 7.25 in x 8.25 in Weight approx. 6 lbs