Many of these units rely on a smoker box filled with either wood chips or pellets to produce the smoke that flavors the food, though some burn wood or charcoal. Models for indoor use typically have a valve that holds the smoke inside the cabinet during cooking that can be turned to release the exhaust before the door is opened. Many also offer moisture controls to prevent meats from drying out during the low-and-slow process of smoking. Outdoor models have a chimney to release smoke.
The commercial meat smoker can move beyond just being that, with capabilities to prepare a whole range of dishes. While the smoke is optional on some models, it can also be used to infuse a new layer into everything from vegetables to cheese. That's why a commercial smoker could be a great addition at plenty of restaurants.