How To Recover The Normal Size Of The Acoustic Foam: 1. After opening the Vacuum package, place the Acoustic Foam in a ventilated place for 12-24 hours; 2. Or soak the foam in water for 1 minute, wring it dry, then air dry or use a blower dry. Low-Cost Noise Reduction Solutions: cost-effective noise reduction products can create an excellent listening or recording environment , you can get a good recording experience or in the studio. High-Density Flame-Retardant Material: The sound absorbing foam panels is made of flame-retardant and environmentally friendly materials, which can be used safely. For professional acoustic control, sound dampening, acoustic treatment, noise reduction - Reduce waves, reverb and flutter echoes in smaller to medium sized rooms. Installation Method: It is recommended to stick the tape to the four corners of the back of the acoustic foam panels, and then to the wall. Or you can purchase glue to install the soundproofing foam according to your needs. Multi-Function Use: It in Home Theaters, Studios or Gaming Room for acoustic treatment / Isolation Shield , or in offices as a Desk Privacy Panel. Also Perfect for in recording studios, home theaters and karaoke room.Can handle walls, ceilings, doors, etc. colour: black Material: polyurethane Size: 12x12x48cm Package Contents: 4 x Soundproofing 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 a little different from the real thing. The measurement allowed error is +/- 1-3cm.