The Precision 5902 (HF5902) Left Hand Side Brick lines the sides of the firebox in your Hi-Flame Precision 5902, protecting the steel walls from direct flame and retaining radiant heat. Side bricks are consumable parts that wear with use, and this genuine spare is made to the correct specification for the Precision 5902. Keeping the firebox properly lined prolongs the life of the stove. Simple to replace.