Acoustic material, acoustic panels, and acoustic mats. I purchased these on Amazon and used them for a short time. They show signs of use. Please note the following: I used adhesive to attach them to the wall, so there are marks like those in photos 8, 9, and 10. Some marks are quite noticeable, so please be aware of this. If you are okay with this, please purchase. I believe I purchased these on Amazon for around 2000 yen. How about using them for noise reduction? ★ I will compress them for shipping. The following is quoted from Amazon: 【About Sound Absorption and Sound Insulation】Acoustic sponges help reduce reverberation, flutter echo, sound reflection, and unwanted noise. Professional studio-level acoustic treatment to create a beautiful recording environment. It can help you make higher quality audio and video recordings. 【Features and Size】The size of one soundproofing sheet is 30x30x2.5cm. The sound absorption rate is the same because the density and hardness of each sponge are the same. The sponge is made of polyurethane, which is healthier than fiberglass or rock wool, is fire-resistant, and has no environmental impact. It is also a good idea as a decorative item. You can choose the appropriate color, thickness, and size according to your needs to enhance the beauty of the space and match the interior design. 【Applicable to Various Places】Acoustic panels are indispensable in life! They can be used widely, as soundproofing covers for walls, ceilings, and doors. Also, places such as theaters, movie theaters, offices, and recording studios. Or busy and crowded places such as gyms, subways, stations, and schools. 【Practical Acoustic Material】Anyone can install it! Cut double-sided tape into five-centimeter pieces, attach them to the center and the four corners of the back of the acoustic material, and then stick it directly to the required place. Because it is a flexible material, you can cut it into any size or shape as needed. The soundproofing panels do not deteriorate or tear over time, and you only need to remove the dust.