Review on Ultimate Portable Cordless Tire Pump: Newest Electric Air Compressor Inflator with 150PSI, 3000mAh Battery, and Digital LED Light for Bike, Motorcycle, Balls, Swim Rings by William Stewart

This works great with car tires to supplement and check tire pressure: connect battery, turn on power, use "U" to select PSI, set pressure (I had 29), connect to the valve stem and press the again power switch. The device shows you the current pressure and inflates to the set value - automatic switch-off. It took less than 4 minutes to go from 17.5 to 29psi, no battery heating, no loud noise. I deflated both front tires and only used 1/4 of the battery. Great handy device. One note: Like all LCDs outdoors in the sun, they can be difficult to see, so take off your sunglasses and shade the display. Again, after installing PSI, you no longer need to monitor or control the device. Just lay it down and let it run until it shuts off automatically. GREAT device!