None. Zero. And that's with lots of travel including air travel and hot locations all carried in my pants or jacket pocket. I use a 1.8 Nauti BVC or a Triton mini 1.2 in it. Between the volume loss and the juice hole location, the subohm one that's made for it makes no sense for me. Only way I fill it is with a unicorn bottle or a syringe. Filling with a dropper gets too messy and wastes more time than the others. For that I vape a high PG juice as well for very little cloud when in stealth mode.