Made of polyester fiber,they are no smell and flame retardant.No any risk when you stay in a room with our acoustic foam panels for a long time. You may be worrying- how to choose acoustic panels with good sound proof performance among so many types of sound proof foam panels.However,you can choose us without hesitation.our acoustic panels can effectively abosorb unwanted sound,such as ,standing wave and high noise.Their Sound abosrbtion coefficient is 0.95, which meet most acoustic treatment need. You would not regret after purchasing them home. Be different from other acoustic panels,We have not only upgraded their acoustic performance,but aslo their appearance.Adopt beveled edge and multi-line design.They can be DIY into pinwheel patterns and multi-ring patterns.They absorb unnecessary sound while playing a good role in decorating the wall. for professional studios, video blogger,game room, podcasting, school,home theaters,offices,etc. our soundproof wall panels are self-adhesive,They can be installed to a variety of different surfaces (walls,doors,,ceilings and so on) without any tools.No need any other glue.Our acoustic panels come in 32-piece packs, which on average are cheaper than 6-piece packs acoustic panels. Adhesive color random, do not accept specified Colour:4:Black Material:Polyester fibers Size:12X12X0.4inch Package Contents: 32 x Acoustic Panels Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.