... 2.Refresh the air in the car 3.Improve combustion efficiency and car sound Car Gas Economizer: (CE & ROHS) ... :Features Description:1.It can test the car battery or alternator automatically, and in this ... not, as other electrical devices in your car will drain energy from your battery and ... up, trucks, compact car, luxury car, sport car etc. About how CARNUMEN to test the car batteries, release the air ...