Monessen Outside Combustion Legacy Termination Kit - Single Pk AK4Monessen Outside Combustion Legacy Termination Kit Single Pk AK4 Product Details The Monessen Hearth Outside Combustion Air Kit AK4 is an ideal ventilation solution for your fireplace. Its efficient design ensures the supply of fresh air while sealing off your fireplace from the outside environment. This reduces energy costs and makes your home more comfortable. Features: Fits various Monessen gas fireplaces Allows the fireplace to use outside air for