Marquis by Kingsman 25 Feet Flex Pipe Kit for IDV44 Fireplace Insert I43FK2525 Feet Marquis by Kingsman Flex Pipe Kit for Fireplace I23FK25 Product Details This Kingsman Flex Pipe Kit is designed for IDV44 series fireplace inserts. This Kingsman Flex Pipe Kit comes with 25 feet of 3 inch and 4 inch liners. This flex pipe will allow the hot and cold air to flow through the 2 separate liners; one designed for airflow in to help combustion and, therefore, the other to release heat and exhaust gases safely out. This item is built