Castaldo® White Label® contains a high concentration of pure natural rubber making it firm but flexible. A good all-purpose mold rubber that cuts well, and is well-suited for thin molds. Vulcanizes at 310°F for 15 minutes per 1/4" of mold frame thickness. Rubber is 1/8" thick and supplied in a box of 5 lb. strips (2.875" x 18"). Also available in Ready Cut, see "Related Products" below. Made in USA.