Evans EMAD™ Heavyweight series features a 2 ply of 10mil + 10 mil film providing an ideal balance of maximum attack, low-frequency response & durability. The unparalleled industry standard Externally Mounted Adjustable Damping (EMAD) system allows the player to adjust attack and focus.  The combination of films reduces frequency of motion, creating pronounced low frequency response with an accentuated attack.  20 mil thickness procides maximum durability for the heaviest of hitters. If you're looking for the maximum punch from your kick drum then look no further, the Evans EMAD Heavyweight punches above it's class! OXYGEN MUSIC is proud to stock a huge range of Evans drumheads including the Emad Heavyweight Bass Drum Heads.