How many tyres can this inflate on a single charge?

This will depend on the required PSI and the tyre width, amongst other factors. In our testing and shown on the product page, it can pump 4 tyres at 65 PSI (28mm tyre), 3 tyres at 80 PSI (28mm tyre), 2 tyres at 100+ PSI (25mm tyre) on a single charge.

How long will it take to inflate my tyre?

This will depend on the size of your tyre, the width of your tyre and your desired pressure.  For reference, for a 700c road bike tyre at 25mm width, you are looking at around 1 second per PSI.  So to reach the max PSI of 120, it will take around 2 minutes.   

What is the maximum PSI this device can inflate to?

This device can inflate to a maximum 120 PSI on a road bike wheel at 25-28mm wide.  

Can it detect PSI even if I am not using it to inflate a tyre?

Yes, it can.

Can this be used to inflate MTB tyres?

Yes it can.  However, due to the width of MTB tyres, it will take longer to reach the same level of PSI compared to road bike tyres.  

Can this be used to inflate tyres with TPU inner tubes?  I heard that electric pumps overheat the valves?

It is true that some electric mini pumps may not work well with TPU inner tubes, where there is resin material connecting the valve.  However, with ours this issue can be resolved by the use of an extension hose which will come with the pump itself.  If the TPU inner tube comes with an entire metal valve, this is not an issue at all and the pump can be applied directly.