Thin foam, over a area, has less of a of distorted and muffling the sounds reverberation. The uniform wedge help trap airborne noise while alleviating flutter and slap back. This foam is Perfect for spot-treating production studios, practice rooms or home entertainment centers. Also, this foam helps with smaller complications. It is tested to effectively eliminate sound waves and flutter. Purchasing your own foam is the to tune your area without hiring a professional acoustician. Foam will not deteriorate or fall apart over time. All that is required is dusting over long periods of time. Item No.: Triangular Slot Shape: surface uneven Product features: sound absorption and noise reduction, sound insulation, elimination, improvement of timbre, reduction of reverberation, beautiful decoration, environmental protection and retardant colour:Black Material:foam size:30 x 30 x 2.5cm Package Contents: 50 x studio foam 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.