Vermont Castings 30000776 3/4" Flat Window Gasket. Keep your Vermont Casting stove running efficiently and safely by replacing your old window gasket with a new Vermont Castings 30000776 3/4" Flat Window Gasket. Over heating, excessive use and abuse are some of the main reasons for gasket failure. Smoke and fumes and sometimes even ash can escape from worn out gaskets of wood burning stoves, and Gas burning and Electric stoves often rely on sealed chambers to run efficiently. Replacing the gasket around the glass doors in your fireplace is simple solution to help with each of these problems. When replacing the Glass, Vermont castings also recommends replacing the old gasket with a new one at the same time. The Vermont Castings 30000776 3/4" Flat Window Gasket is a 3/4 inch wide, 3/16" thick, and is sold per foot.