The Graphite 5 (GR905) Side Fire Bricks lines the sides of the firebox in your Hi-Flame Graphite 5, 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 Graphite 5. Keeping the firebox properly lined prolongs the life of the stove. Simple to replace.