Which electric pump

[TrekCentury]

Mini Electric Pumps

So I did the noosa triathlon today and I am one to try and avoid taking a track pump with me due to the bulky nature of the thing to carry. There was a guy in transition with an mini electric pump and I was like that is a winner. Have been seeing adds etc on Facebook for them of late and now I am curious and keen to buy one. Maybe one that can easily be carried in the pocket to inflate tubes on the go. Can anyone share their experiences, brands to buy or avoid please?