This product is sold as 2 pack best for when absolute sound deadening is not required, but moderate deadening is desired. Acoustically, they smooth out the excess frequency energy that congregates in room corners. Use: Perfect for use on corner walls, corner ceilings, etc. Anywhere to help block sound and prevent echoes inside the room. Best When You Cover The Corner From Top to Bottom, with this Product. Thin foam, over a large area, has less of a chance of distorted and muffling the sounds reverberation. The uniform wedge design help trap airborne noise while alleviating flutter echo and slap back. This foam is ideal for spot-treating production studios, practice rooms or home entertainment centers. Also, this foam helps with smaller agitation echo complications. It is tested to effectively eliminate sound waves and flutter. Purchasing your own foam is the best way to tune your area without hiring a professional acoustician. This Foam will not deteriorate or fall apart over time. All that is required is dusting over long periods of time.