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 to dry it. High Quality Materials: Our sound absorbing foam panels are crafted from fire-retardant and eco-friendly material. It is safe to use in small and medium-sized rooms. High quality panels for better sound absorption, reduce waves, reverb, and flutter echoes in smaller to medium sized rooms. The principle of the soundproofing foam is that the sound inside the sponge is repeatedly reflected back and forth, thereby achieving the effect of noise reduction and sound absorption. The acoustic panels not only have effective sound absorption characteristics, but also will not cause any harm to our body. The high quality material studio foam can keep its sound insulation function permanently. In terms of cleaning, you just need to vacuum and dust them occasionally. 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. Widely Use: The soundproofing foam squares are a low cost solution to get better recordings in the studio. For professional recording, video and game live broadcast, these panels are suitable for professional studios, rehearsal rooms, concerts, podcasting, churches, home theaters, vocal booths, and home environments. Size: 30x30x2.5cm Material: Polyurethane foam Color: White Package Contents: 12 x Sound-absorbing cotton Only the above package content is included, other products are not included. Note: Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The measurement allowed error is +/- 1-3cm.