These are device that you put pure wood pellets in and use in your grill or smoker. For my electric smoker this gives me much more control over the amount of smoke and I can mixed pellet types. Electric smokers tend to produce smoke with wood chips when the heating element is on. These devices produce smoke all the time there are pellets burning in them.
https://www.amazenproducts.com/Default.asp
I mostly use the wedgie for meats and the tube for cheese or beef jerky. The tube does not burn as long.
I added stainless steel feet (screws) to mine so they sit above the floor of the smoker.