The P20iX is a tacticool type 21700 size light. It's very floody - perfect for inside buildings or close range outside where you need a big field of view, and bright enough at 4000 lumens .
The bumps on the front are something super tough for breaking car windows etc - so I guess aimed at first responder types. I quite like the double clicky tail switch. One is a really solid on/off click and the other cycles between light levels.
It has two modes, I use it in the everyday mode where it remembers the light brightness from when you turned it off. There also a hard core mode where it always turns on in max.
The hard plastic holster has a hole in the bottom, which I assume is to avoid melting it with the 4 x 4 x CREE XP-L2V6 leds, but I have occasionally just turned it on in the holster for general lighting if I needed both hands.
Since it's quite easy to pull it out of the holster, I do have a slight worry that it will come out by itself if I'm clambering around somewhere - but it never has yet. The holster is intended for clipping on those massive duty belts - it would swing around a bit otherwise. I have a vague recollection it came with some clips to use on narrower belts but perhaps I've thrown them away.
The 21700 battery it needs is a weird Nitecore one with positive and negative contacts each end. I wasn't wild about that, but in practice I never carry spare batteries, so they can be weird or built in and it's no particular problem. If you really hate this idea, there is an optional caddy for 2 x cr123s - but less brightness and lower run times.
Oh, that thing with the battery would piss me off. I have a burning hatred of nonstandard batteries. I don't often carry a spare, either, but I an much more interested in knowing that in 2-3 years when the original battery is toast I can just take another one off the shelf and move on with life.