The kick fits in the P+18500 very snugly with 1 thin o-ring below the battery and no washers under the negative post. The last full turn of the top cap has a fair amount of resistance, but it's not to difficult to get it to screw down all the way. Everything is nice and tight, and it performs fantastic! Granted I have to carry 2 18350's around in addition to the one installed in the pv to have enough battery power to last all day, but I am used to carrying around 4 16340's with the P+16, so not a big deal to me. I really love the size of the P+16, but the performance of this setup rivals any VV device out there.
Thanks alot

And of I go ............