Sierra Flame Stanford Series Fireplace Insert Fuel Conversion KitStanford Series Fireplace Insert Fuel Sierra Flame Fuel Conversion Kit Product Details Do you love your 55" Stanford direct vent linear fireplace, but tired of using and replacing those propane tanks? Or have you decided that you don't want to use natural gas? Look no further. This conversion kit is your answer. While it is manufacturer specific to Stanford, the kit is designed to alter the opening size of your gas valve to accommodate different BTUs