ProQ - Smoker Stacker 17" - Frontier Version 4.0 (2019)ProQ Smoker Stacker 17" Frontier Version 4. 0 (2019) This ProQ stacker will increase the capacity of your ProQ V4 BBQ Smoker by a whole grill, adding an extra 50% grill space! Made from the same high quality as the rest of our ProQ V4 barbecues, this stacker is built to last and comes in 3 sizes to fit each of our BBQs. Features: Strong porcelain coated body, aluminium door and stainless clips, grills and handles. Add an extra 50% grilling space to