How to Restore the Normal Size of Sound Absorbing Foam: 1. After opening the vacuum packaging, place the sound absorbing foam in a ventilated place for 12-24 hours; 2. Or soak the foam in water for 1 minute, wring it out, and let it air dry or use a hairdryer. High-Quality Materials: Our sound absorbing foam panels are made of flame-retardant and environmentally friendly material, it is safe to use in small and medium-sized rooms. High-quality panels for better sound absorption, reducing waves, reverberation, and flutter echoes in small to medium-sized rooms. The principle of 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-absorbing properties, but will also not harm our body. The high-quality material of the studio foam can retain its soundproofing property permanently. As for cleaning, you just need to vacuum and dust them occasionally. Installation Method: It is recommended that you attach tape to the four corners and the middle of the back of the acoustic foam panels, and then attach them to the wall. Or you can buy spray adhesive to install the soundproofing foam according to your needs. Wide Application: Soundproofing foam squares are an inexpensive solution for getting better recordings at home or in the studio. They are used for professional studios, rehearsal rooms, concert halls, podcasts, churches, home theaters, singing booths, home studios, offices, man caves, dog houses, storage rooms, and more. Size: 30 x 30 x 2.5 cm Material: Polyurethane Color: Black + Gray Package Contents: 12 x Black Soundproofing Foam 12 x Gray Soundproofing Foam Only the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3 cm.