Superior 50-piece Bulk Outside Air Kit - Collar Only Kit AK4BUpgrade Your Fireplace with Superior 50 piece Bulk Outside Air Kit AK4B Why is the Superior Collar Kit the best for my Fireplace? The Superior VCM3026 Series 26 inch, 50 piece Bulk Outside Air Kit (Collar Only) Kit AK4B is designed to provide a bulk outside air solution for your fireplace. Key Features Facilitates the efficient intake of outside air to support combustion. Helps maintain indoor air quality by reducing the reliance on indoor air for