Heatilator Firebrick Yellow Hearth Refractory (Birmingham), 36" - 50". Options - Size: 36"; 42"; 50". Conversion kits and replacement parts are specific to the appliance model and fuel type. Confirm your model number and whether you are running natural gas or propane before ordering, and have the work performed by a qualified installer following the manufacturer's instructions so the appliance keeps its listing. Special order - contact us for a quote.