✨【3D Acoustic design】Thick, 2 inch foam can be used to absorb lower frequencies to control and trap bass; and to control and trap echoes，providing the ideal level of moderate sound control on walls or ceilings | ✨【Environmental and safety】These acoustic foam panels are Made of quality polyurethane High density flame-retardant foam material,odorless,non-toxic, fireproof, durable, efficient and safe to use. According to UL 94 flame retardant test, we get grade 94 HF-1 | ✨【Expands quickly】 Our foam panels come compressed in a vacuum package and quickly recover to normal size, either by placing in a well ventilated place for about 24-48 hours or soaking the foam in water for one minute then wringing the water out and using a hair dryer or letting it air/sun dry | ✨【Easy to Install】These studio sound absorbing panels can be used as acoustic cover for walls, ceilings and doors, just easily attach it with staples, nails, screws, tacks or glue | ✨【100% satisfaction shopping】These soundproofing foam panels come with 12 pack purple+12 pack black in the package,“Contact Seller” if you are not happy with the purchase or have any questions. Our Excellent customer service will leave you with no worries after you buy it