Class PL pipe is a venting system capable of handling the exhaust from appliances that burn wood pellets with temperatures up to 570 degrees continuous and operating under a forced draft. Despite the double wall construction the outside shell of this pipe still gets hot and requires an air space. The metal used on the outside is galvanized steel or stainless steel and the metal used on the inside is stainless steel. Lengths range from 6″ to 60″ and diameters range from 3″ to 4″. We supply & install these products.