This is sound-absorbing material for car deadening, called "Magic Insulation Jacket." It's best used in conjunction with deadening sheets (vibration damping sheets). 【The Latest Buzz in Sound Absorption, Here's What's Amazing!!】 ・Material Matters! By using plenty of PP (polypropylene) and PT (polyester) materials and layering them, it achieves higher effectiveness than general felt materials! ・As shown in the installation example in the image, you can feel better sound quality by installing it inside the door. You'll notice a difference not only with music but also with TV sound! ・Due to its heat insulation and heat retention effects, your air conditioner will work better, keeping you cool in the summer and warm in the winter! ・In fact, it's made of the same material used in bullet trains! We wanted to deliver a higher-quality product because it can be used permanently once installed. 【3 Effects in 1 Sheet!】 Insulation: PP material has excellent insulation properties and is effective regardless of humidity. Heat Retention: Reflects external heat. The thermal conductivity is as low as s0.030W/mk, maintaining a comfortable temperature with minimal energy. Sound Absorption: Eliminates phase shift by suppressing sound reflections (improves the sound quality of sound systems). 【Size】Approximately 80cm x Approximately 50cm Quantity: 2 large sheets If you need a different quantity, please inquire in the comments section. Shop Kaze Kobo also offers many other products, such as headlights, fog lights, and sound quality improvement sheets, so please check out the hashtags and my page! #shopKazeKoboSoundQualityCommittee 【Product Description】 Material: Material made by layering polyester and polypropylene Heat Resistance: Non-flammable Usage: The back is fully adhesive, so you can easily cut it to your desired shape. There's no need to worry about it peeling off from the edges. 【Impressions】 This is my personal experience using it. Regarding sound quality, it has improved dramatically. There is no echo, and the sound reaches my ears directly, making it pleasant to listen to. I was impressed, thinking, "So this is the original sound of the speakers." Recommended for those using Regetrex, Real Schild, and other deadening vibration damping sheets, vibration isolation materials, and damping materials. We support those who are challenging deadening with DIY!