The box I built will do both, it hot holds at a steady 165' and there is a damper where I can open up the chamber to more heat and smoke. I have even used it to smoke sausage. I designed the warming box to hold full size hotel pans and also have a few wood dowels to hang sausage. There is a damper right on top of the firebox built out of 6" pipe with a screw-type lid that can be opened as little, or lot if needed. The box will hold 25 butts(5 on each rack).