MuteX Soundproof Material (Black, 40 sqft, 5'x8') Compact & Lightweight at only 1/4" thick and 1/4 lb/sqft 2x Stage Sound Barrier with Polymute Resin and Carbonweave All Weather Tempature Range from -50F degrees to 350F MuteX is made in the USA and has an STC rating of 32. Used in Automotive, Industrial, Commercial, Home Construction for HVAC, Walls, Floors, Ceilings, Doors, Condominiums, Motors, Trunks, Speaker Boxes, Recording Studios, Curtains, etc.