Very portable and useful aid for muscle soreness and recovery!
I'd been looking at this type of massage gun for a while, but many were extremely pricey or very large (or both!) This is a good size for carrying around in a gym bag or to sports events, measuring less than 6" x 5" with a massage head attached and the handle is around 1 3/4" in diameter.
There are 4 settings that adjust on the the head vibration speed - they don't adjust the depth of massage in any way that I can see, which stays at around 6-7mm. This is deep enough for decent relief, but is a lot less than the larger (and more expensive) therapy guns, some of which have a depth of around 10-12mm.
Importantly, the vibrations aren't passed to the handle much - you can feel them, but even after 10-15 mins use there's no numbness on my hands. One slight (and only slight) negative is that because it's small, it can be a bit of a stretch to reach around to massage parts of your back.
Personally I've found the round and 'finger' heads most useful in general (though the pointed head is quite good at getting deeper into large muscles if you use a bit of pressure), with the speed set at 2 or 3, for post run massage of thighs and calves.
All in all a great little gadget to have!