Insulated heater jacket thermostatically controls water in weather conditions down to -10 degrees F (-23 degrees C). High?visibility yellow, waterproof insulated jacket made of 200 Denier foam?backed nylon w/clear vinyl pocket. LED indicator lights ensure proper operation of heaters. GREEN means power is ON. AMBER means heaters are in operation. RED means unit has malfunctioned. This will automatically shut the unit off. Pulling front strap down and away from unit activates eyewash.