Astria Outside Air Kit Collar, Hood and 3 inch Flex Pipe for Floor Venting AK4FAstria Outside Air Kit Collar, Hood and 3' Flex Pipe for Floor Venting AK4F Product Details What is the role of the Astria Outside Air Kit with Collar, Hood, and 3' Flex Pipe for Floor Venting, and how does it enhance the air circulation and efficiency of a fireplace system? The Astria Outside Air Kit with Collar, Hood, and 3' Flex Pipe for Floor Venting is designed to enhance the air circulation and efficiency of a wood burning fireplace by supplying