Acoustic panels purchased about a year ago. I tried to attach them to cardboard boxes with spray adhesive, but it didn't work out as planned, so I'm putting them up for sale. Since I used spray adhesive to attach them to the cardboard, some panels still have cardboard surface attached when peeled off. Some parts of the acoustic panels have slightly yellowed due to the spray adhesive. Nails for installation are not included. Please check the images carefully and consider purchasing only if you understand the condition. Soundproofing/Acoustic Absorption Board, 50 pieces Size: Approximately 30cm x 30cm x 0.9cm Please purchase with the understanding that these are used items. No returns or exchanges under any circumstances. I look forward to your comments. [Soundproofing Material] It has excellent sound absorption properties and is ideal for creating a quiet environment. [Easy-to-Use Size] With a thickness of approximately 0.9-1cm, it can be cut and processed for various purposes. A set of multiple pieces can cover a large area. - Color: White - Condition: Some stains - Quantity: Multiple pieces - Application: Soundproofing/Acoustic Absorption Material