PRODUCT DESCRIPTION Rubber sheet fiber yarn RUBBER cloth-inserted materials are designed to add stability where mechanical fastening is Necessary, and to reduce flange gasket creep where heavy loading is required. For the low line pressure applications such as water, hot and cold water, saturated steam and low pressure steam.s a smooth-finish SBR / NBR sheet, constructed with polyester fabric. One ply of fabric in 1/16 "(1.6 mm) through 1/8" (3.2 mm) thicknesses. Two plies of fabric in 3/16 "(4.8 mm) and 1/4" (6.4 mm) thicknesses.