Shell is made of glass, and there are two tubes, when a tube needs cleaning use another tube.
This is the best rda, It does not leak liquid. 22mm diameter suitable for any 18650 Mods.
The bottom is four vents, Prevention of high temperature combustion of cotton or coil.
Can bring a lot of stability vapour and have not sickening smell.
You can assemble in yourself, but should not give a child the age of eighteen to use.