I bought my Silicone rubber sheet from Abbott Rubber Co., Inc. They are located in Elk Grove, IL and their LL# is 847-952-1800. They will sell a minimum of 1' x 3' and the cost of this is $35.11. Their part No. is 5810-0125. It is red, 1/8" thick and works really well as a chimney. Bob Maser W6TR