I still have a few 12" x 26" x 3/16" Silicone rubber sheets available. They make wonder ceramic tube chimneys and plenums. $20 plus $10 US Priority Mail shipping. This is the same material that is available at McMaster-Carr for $30 per square foot plus shipping and handling. I will take your check or MO. No PayPal. I am good on QRZ.com. 73 Bob W6TR