Thank you for viewing. This is a set of soundproofing materials, new (purchased as a set of 5, with only 1 used, so the remaining 4 are a set). The plastic bag is open, but the items are unused. They were only taken out for photography. I think they can be used for DIY projects, etc. 【Size】50cm x 50cm x 4 sheets (Thickness 5.0cm) * 【Size】Outer dimensions: Approximately width 50 x depth 50 x thickness 5.0cm (per sheet) (set of 4) * 【Material】Sound-absorbing material: Non-halogen flame-retardant foam * * Adhesive such as double-sided tape or spray glue is required for attaching to walls, etc. * 【Recommended points】 ・Non-halogen flame-retardant foam does not use halogen-based flame retardants! ・Flame-retardant foam that is environmentally friendly ・Excellent sound absorption ・Passed flame resistance tests (UL-94)(HF-1) ・Suppresses sound reflection, and slight reflected sound is directed in various directions