The Heat Diffuser Plate may be placed on the bottom grate level and used to disburse the direct heat from the fire basket creating a more indirect heat source effect. It is a perfect accessory for cooks desiring a low & slow cooking method. Fits 55 Gallon Gateway Drum Smokers. Important Delivery Information This product is on backorder and is expected to arrive at Great Northern Larder in mid April. This means you need to allow for a period of waiting before you receive delivery.