Trident Propane Detector Additional Unit, #1300-7720, for use with propane control systems #1300-7760 and #1300-7761. Marine UL Listed with red function light. Remains ON and monitoring even when gas control panel is OFF. Its sends an alarm signal to the control panel when an LP gas is present at 10% Lower Explosion Limit (LEL) or more. Up to 2 additional gas detectors can be easily added to the systems with either the 10 ft. or 20 ft. quick connect cable (#1300-7721-120 and 1300-7721-240 respectively). Each draws 163 mA.