The AA 12V digital inflator is the pump you want before a slow puncture ruins a bank holiday. Set PSI, screw onto the valve, plug into a live 12V socket — it stops on its own within about 1 PSI of our track gauge.
It is loud (it is a compressor), and there is no carry bag. The screw thread is slower than a clip but leaks less on a frosty valve stem — worth the ten extra seconds.