Engel front-open in-cab refrigerator models are available in 42- and 60-quart capacities. The spring-mounted swing motor compressor, which has just one moving part, draws minimal power, the company says. The motor is in a fully sealed chamber to isolate it from vibration. The cooling unit uses a CFC-free refrigerant gas. Engel units will automatically switch from 12/24 volt DC to 110 volt AC, depending upon power availability, with a current draw of 3 amps or less.