I have a Fumpa nano. Works great as a back up to the topeak and will inflate a typical road tyre from flat to hard in 30 secs. Ive used it a couple of times when the topeak gets so far then becomes really hard to get to full pressure. It is about the size of a matchbox. I’d not rely only on the Fumpa but find it reassuring to have a mechanical aid when tired. One warning, don’t use near those of sensitive dispositions as it gives out an enormous farting noise!
I love the name Fumpa for a pump! Conjures up an image of a great big steam driven bellows going "fumpa-fumpa-fumpa" whereas it's a tiny buzzy, farty electric gizmo.