Hi, The person I bought my chargriller duo from had added, or perhaps theirs came with the smoker box attached. (Here is my model I am using other smokers, and also due to size, have decided to dismount the smoker box until I actually need to use it. This however left a void, a hole where the 2 connected in the side of the grill. The oppening where the smoker box sent smoke into the cooking chamber. On the models without the smoke chamber, there is a metal plate bolted in, with an oxygen control doorway, that can be removed to add the smoker box. Try as I might, I cannot seem to find anywhere online to buy that plate replacement, I have found the full cooking chamber replacement with the plate on it, but I would have thought it was a more common part. I also tried using the charcoal slide out tray from the smoking chamber itself, but it doesn't fit, and would also prevent the use of the adjustable charcoal tray if I did. Here is the new hole I am talking about: Anyway, if anyone can find the part somewhere online or knows where to find it, please let me know!