effectively reduces unwanted echoes, waves, reverberations, and tremor echoes, making other sounds clearer. It can also be used as for bedroom soundproofing.Each acoustic wall panel can cover about 1 square feet(12 Pack covers 12 square feet). The larger the coverage area, the better the sound insulation effect. The sound absorbing panels are self-adhesive backing designed so you 't need to buy glue. The polyester material is easy to cut and stick to surfaces such as windows, doors, walls, fabric, glass. (TIPS:A blower you may need if you want lay, attach, apply, and remove the panels without damaging the surface. blow the acoustic panel surface with hot air until the glue soft and easy to remove from the wall.) soundproof panels are perfect for spot treating sound on walls in your studio or office, recording studios, classroom, bedroom, offices, home studios, and home entertainment theaters. They are also easy to shape and cut to size, making them perfect for use on the ceiling, behind the TV, or under your rug. with adhesive backing, the color is random, no designation is accepted Colour:Silver-Gray Material:Polyurethane Size:About 30x30x1cm Package Contents: 12 x Acoustic Foam Panels Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.