The OPT-1 is a dual instrument which features dual 90 degree graphic analog displays. Select to view pressure or temperature on the digital display using the toggle switch on the front panel. OTP-1 measure to 1 PSI and oil temperature to 1°F on the digital display. It incorporates an external pressure transducer and temperature probe that are mounted in the engine compartment. The instrument is backlit for night operation and operates on 12 or 24V system. Oil pressure range is 25-100 PSI and oil temp. range is 65°-240°F. Wt. 22 oz.