I have one. It is a "beer can turkey" device. You put liquid in the "cannon" (hollow tube). Works okay. Comes with a cheap brining kit. The "cannon" works best at roasting temperatures (350 up) and it helps to pre-heat the liquid so that it steams even at the start. Doesn't work well and really wasn't designed for smokers where the ambient temp is just barely above the boiling point of water.
I like injecting my turkey with EVOO and a little bit of butter and a tinge of garlic before roasting in a bag better.
Hub