The Xiaomi compressors are mainly designed for inflating air and do not offer a function for targeted deflation. If you want to deflate a tyre, you have to do this manually by opening the valve nozzle. However, the compressors are equipped with an automatic switch-off function as soon as the desired pressure is reached, which makes inflation easier.

I use the compressor (Pro) to inflate tyres on cars, bicycles etc. It is relatively loud. It is relatively loud. A bicycle tyre is inflated quickly and with a car I usually only increase the pressure by 0.1 to max. 0.5 bar, which is also very quick. But it's probably not the right device for a SUP. A SUP is huge and would probably take ages to fill up.

You cannot use the compressor directly for a stand up paddle as it is mainly designed for car tyres, balls and bicycle tyres. Stand up paddles often require higher air pressures and special valves that may not be compatible with this device.

Yes, you can also depressurise the appliance. To do this, connect the quick-connect nozzle adapter to the American nozzle and press the quick-connect nozzle to release air.

The Xiaomi Air Compressor 2 Pro is mainly designed to pump air into tyres or other inflatable objects. It has an automatic pressure detection function that stops it when the preset pressure is reached. There is no specific function that allows air to be released from a tyre by reducing the pressure. So if you have a tyre with 3 bar pressure and you have set 2.8 bar, the compressor will not automatically release the excess pressure. You would have to manually reduce the pressure by releasing air from the tyre before using the compressor.