Because it's not the size that matters...
The H.S.P is the only pump you'll every need for you PEV! This bad boy will fit basically anywhere. It's hella light, it can hit up to 150 PSI and it even has a freakin' light on it! This thing is super ill and you should definitely pick one up!
Keep it in your car, your backpack, your pocket, it don't matter this thing will fit anywhere... Well... Maybe not everywhere.... Please don't try to put this in your butt...
Picked one up so I could change my tire pressure while I'm out away from home and ended up using it to air up a flat car tire a time or two! It's not super quiet, and while it makes quick work of Onewheel tires and I highly recommend it for that, just manage your expectations when it comes to a full size car or truck tire and know that it'll take 5+ minutes or so to air up, and use about 50% of the battery. But... it WILL pump up a car tire in a pinch! Nice.
Got the TFL HSP for its 0.5 PSI increments. I like its smaller, handier form factor, and having separate readout and desired PSI numbers is a huge usability plus. One small caveat detaching the pump tube (the TFL video is misleading): Do NOT push on it, it's supposed to protrude a little bit so it can be easily pulled out. It's not a spring-based push-click mechanism, it simply locks in by what feels like a notch. NGL I was pushing on it pretty hard wondering why mine wouldn't click in or spring out until I realized how it was supposed to work. No damage (knock on wood), pumping fine.
Amazing product from an amazing company!
Literally fits in all my pockets and that small pouch in my backpack. Great size great function works properly even after spilling water on it.