Usage Tips:[Eco-friendly and Safety]Made of environmentally polyurethane foam, these studio foam are durable and effective, no health risks, safe to use. [Noise Absorbing]Our sound foam panels can dampen and diffuse mid to low frequency sound waves inside of a room, to minimize interference, increases increasing sound . [Easy to Install]These studio sound absorbing panels can be used as acoustic cover for walls, ceilings and doors, just easily attach it with staples, nails, screws, tacks or glue. [Widely Usage]Our sound dampening foam panels are great for recording studios, vocal booths, control rooms, also perfect for home theaters, movie theaters, concert and more. How To Recover The Normal Size Of The Acoustic Foam: 1. After opening the Vacuum package, place the Acoustic Foam in a ventilated place for 12-24 hours; 2. Or soak the foam in water for 1 minute, wring it dry, then dry or use a blower dry colour: black + red Material: polyurethane Size: 30x30x2.5cm Package contents: 25 * black sound-absorbing cotton 25 * Red sound-absorbing cotton Warm Tips: Foam will not deteriorate or fall apart over time, all that you need to do is to clean the dust after long time use. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.