Pretty decent electric bike pump, smaller than a pack of cigs. Enough to pump 700x40x tires to 3bar about 2.5 times.
Yesterday due to me being not careful I lost all air in the front tire, like it was completely empty. This thing not only pumped it up back to normal running pressure in about a minute, but also put the tire (tubeless) back on hooks -- I've heard it click in place at least twice.
Beats small hand pumps handily, but I still have one for backup -- battery is obviously not that stellar. Also gets hot as fuck, so probably not a smart idea to keep in your pockets.