Double-ply construction with 7-mil outer ply and 10-mil inner ply Rugged durability offers long-lasting playability Externally mounted adjustable damping system lets you dial in your tone and attack Boasts Evans' Level 360 technology for totally even contact with the bearing edge Batter/Resonant:Batter Size:20" Clear/Coated:Clear Thickness:16.5mil (1 x 10mil, 1 x 6.5mil) Manufacturer Part Number:BD20EMAD2