The box is packed with cotton wool which is surrounding the element and soaked in smoke fluid (in this case baby oil) but leaving a passage through the center for air flow. I'm waiting for a couple of air pumps to arrive but I've used the old smoker unit pump again to demo the smoke and pulsing, (makes good smoke rings too)😊
The element is capable of taking 4.5v, but I'm only using 2v for the test and it smokes quite well. The pump is running on 7v but can be varied from around 3v - 8v. The large tubes are to allow for later exhaust fitting (water or dry stack). Once I get the air pumps I'll be running this one with the water again. I've done this (like Grahams version to be able to easily replace the element as the Heng Long smokers, while working ok (but noisy) have non replaceable elements, so if you kill one, it's off to file 13 at the end of the bench😉😁
The pump actually works quite well and if you mount it on sponge rubber it is reasonably quiet and could still be useful in a boat with a bit of interior room.
Cheers Colin.
JB