The Smith custom-sized Fire Patrol "G" is constructed of heavy galvanized steel in both the baffles and the one piece frame. Steel rivets secure the frame at one corner.
Two layers of roll-formed baffles are equally spaced, creating an air flow which causes grease to collect and drain down the baffle. Properly located drain holes in the frame allow the grease to drain into a collecting trough. The Fire Patrol is designed to prevent flame from passing through the filter.