5 SECOND FAST HEATING- 800W High Power Car Heater made by PTC ceramic heating element . Provide the comforts for travel, camping, glass defrost mist. (800W heaters are more efficient and versatile than other products.) MULTIFUNCTION -Used for Windscreen defrosting, demisting and deicing. And preheat the coolant of the engine to avert wear and tear of engine that started at low temperature. COMFORTABLE - It can be installed at the bottom of the seat, next to the foot or at any position on the car. Safely and comfortably get on the road and get to your destination. UNIVERSALLY - The heater can be applied for heating 12V car (Gasoline engine ), storage battery cars,RV and all kinds of other vehicles. Check the car battery is 12V or 24V.The red line is connected to the positive (longer need extra wire 10 gauge), the black line is connected to the negative, and you can add an inline at least 50A fuse. Please contact us if you need installation instructions NOTE - 1 year warranty Guaranteed If power can't reach 800W, not because of the product, but because of the lack of battery current. If the current is small, the power will not reach the peak power. So you need to change the battery above 45AH. The larger the AH, the greater the power. When the battery is fully charged, it can reach the peak.