METAL INFLATABLE STRUCTURE: Its composed of metal cylinder and metal gear, it could continuously work for 20 minutes, the maximum air pressure could reach 160psi, meet the needs of 4 tires at a time, more efficient and faster to use. DUAL POWER SUPPLY: DC 12V power supply and 20V rechargeable battery pack power supply make the inflation more easily. The bottom is stable enough. You don't have to worry about it running out of the battery during the trip. This item includes a battery and a charger(The Battery and Charger are also sold separately). AUTOMATIC SHUT OFFLCD PRESENT MORE: Preset the value you desire and the air compressor will automatically shut off when the value is reached. The back-lit LCD screen will display both the desired tire pressure value and the current tire pressure. The unit of air pressure can be switched among bar, kpa and PSI. FAST INFLATION & CHARGING: Air/Electricity The 20V working voltage provided by the rechargeable battery can inflate fast, tires of size