Evans EMAD2 Clear Bass Drum Head, 20 Inch 20" drum head made using two plies of film. An outer ply of 6.5mil and an inner ply of 10mil film Externally Mounted Adjustable Damping system allows the player to adjust attack and focus Very versatile head for all music genres; a true working drummer's choice All Evans drum heads are designed, engineered and manufactured in the USA