High-Density Flame-Retardant Material: The sound absorbing foam panels is made of flame-retardant and environmentally friendly materials, which can be used safely. At the same time, it can also improve sound quality: by absorbing harmful sounds, reducing fluctuations, reverberation, and vibrating , Useful sounds are clearer. Low-Cost Noise Reduction Solutions: cost-effective noise reduction products can create an excellent listening or recording environment , you can get a good recording experience or in the studio. Installation : It is recommended to stick the tape to the four corners and the center of the back of the acoustic foam panels, and then to the wall. Or you can purchase spray glue to install the soundproofing foam according to your needs. Suitable for professional studio, recording studio, voice studio, control room, rehearsal room, concert hall, podcast, etc., also can be used for church, home theater, professional theater, home studio, office, utility closet, etc.Can handle walls, ceilings, doors, etc. 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 air dry or use a blower dry. Colour: black Material: polyurethane Size: 30x30x30cm Package Contents: 4 x Soundproofing Foam.