Evans GMAD™ series features a single ply of 12mil film that delivers increased low end, punch and power when compared to traditional 10-mil single ply heads. The GMAD contains two interchangeable damping rings that maximize attach and low-end without removing the head or reaching inside the drum. Ideal for heavier hitters looking for a solid sound and more life to the head but prefer the feel of a single-ply. Evans GMAD™ series features 12mil of single-ply film that delivers increased low end, punch and power when compared to traditional 10mil single-ply heads. Ideal for heavier hitters looking for a solid sound and more life to the head but prefer the feel of a single ply., 20" drum head made using a single ply of 12mil film, Externally Mounted Adjustable Damping system allows the player to adjust attack and focus, Ideal for heavier hitters looking for a solid sound and more life to the head but prefer the feel of a single ply, A 12mil version of the original 10mil EMAD, All Evans drum heads are designed, engineered and manufactured in the USA