Evans BD22EMADONX Evans EMAD Onyx Bass Drum Head 22 InchEvans Onyx EMAD single ply bass head contains two interchangeable damping rings that maximize attack and low end without removing the head or reaching inside the drum. Evans EMAD series features a 10mil of single ply film providing an ideal balance of punch, power and low end. The unparalleled industry standard Externally Mounted Adjustable Damping (EMAD) system allows the player to adjust attack and focus. The Onyx version is the perfect aesthetic