1. How to restore acoustic foam to its normal size: 1. After opening the vacuum pack, place the acoustic foam in a ventilated place for 12-24 hours 2. Or soak the foam in water for 1 minute, wring it out, and then let it air dry or use a hair dryer. 2. The principle of soundproofing foam is that the sound inside the sponge is repeatedly reflected back and forth, providing a noise reduction and sound-absorbing effect. Acoustic panels not only have effective sound-absorbing properties, but they also do not cause any harm to the body. High-quality studio foam can permanently maintain its sound insulation function. For cleaning, simply vacuum and dust them occasionally. 3. High-Density Material: Sound-absorbing foam tiles are made of flame-retardant and environmentally friendly materials that can be used safely. The absorption spectrum is wide and exceeds 500 HZ. High-density material, which is higher than the industry standard of 30 percent . At the same time, it can also improve sound quality: by absorbing harmful sounds, reducing fluctuations, reverberation, and vibrations, useful sounds become clearer. 4. Installation: It is recommended to attach tape to the four corners and the center of the back of the acoustic foam panels and then to the wall. Or you can buy spray adhesive to install soundproofing foam according to your needs. 5. For professional acoustic control Acoustic foam is delivered uncompressed and in new condition. With professional acoustic control, sound dampening, acoustic treatment, and noise reduction, the acoustic foam is designed to reduce waves, reverberation, and flutter in small and medium-sized rooms. Acoustic panels are suitable for recording studios, rooms, home theaters, KTV, and all types of public places. color: Blackandgray Material: Polyurethane size: 30 x 30 x 2.5cm Package Contents: 12 x Black soundproof foam 12 x Gray soundproof foam 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 to be a little different from the real thing. The allowable measurement error is 1-3 cm.