This is a homemade soundproof box for a trumpet. It's a wooden box with Daiken's 455H soundproofing sheet, polyester sound-absorbing material Poly Leaf, and gypsum board on the bell side. To maximize soundproofing, it can be sealed, but there's also a hole to directly insert the bell for everyday use. It has double doors, so a flugelhorn bell can also fit if the depth is sufficient. The gypsum board on the corner is damaged. Please note that this is not a commercial product, but a handmade item.