Produced by environmentally polyurethane foam. In order to improve the opening and specific acoustic characteristics, make it not only has the sound absorption characteristics, but also without any harm to human body. Features: Suitable for sound recording studio, listening room, home theater, KTV, and all kinds of public places. The sponge is the ideal sound insulation, sound-absorbing, heat insulation material. Sound-absorbing sponge is on the basis of sponge for further processing, acoustic inside the sponge and reflection of the increase in the number so as to achieve the noise, sound-absorbing effect. It not only has the sound absorption characteristics, but also without any harm to human body. Specifications: Color: red, blue, black, yellow (optional) Material: sponge Item size: 300 * 300 * 20mm / 11.8 * 11.8 * 0.8in Item weight: 20g / 0.7ounce Package size: 330 * 330 * 60mm / 13.0 * 13.0 * 2.4in Package weight: 182g / 6.4ounce Package list: 12 * Noise Insulation Sponge