Evans 24 inch clear EMAD2 two-ply bass head contains two interchangeable damping rings that maximize attack and low-end without removing the head or reaching inside the drum.  Evans EMAD2 series features two plies of film. The outer ply of 6.5mil and an inner ply of 10mil film provides an enhanced attack, focus and durability. The unparalleled industry standard Externally Mounted Adjustable Damping (EMAD) system allows the player to adjust attack and focus.