This PDA (pocket PC) from Mio runs typical PC software, but also has a built-in GPS antenna. Teamed with digital mapping software, such as Memory-Map, the P350 can be used as a walking GPS unit that shows full detail Ordnance Survey mapping. There’s no doubting the appeal of a GPS receiver that shows your exact position on 1:25,000 OS mapping and, in practice, it’s as good as you’d hope. However, the cons probably outweigh the pros for serious walking, as battery life is very low – less than four hours at times. Also it’s not really robust enough for British weather and you need to use a stylus, which is fiddly.