Aquarian RSM24BK Regulator Small Black – Size – 24"The offset ported black Regulator RSM is a single ply, resonant bass drumhead that features a small, centre positioned, "Floating Muffling Ring" for added resonant control. This patented Aquarian innovation eliminates the need for external muffling of the resonant head. This head is the perfect companion for any of the Super Kick bass drum series batter heads. The result is a bass drum that will tune up and mic up in seconds. The small 4. 25