The offset ported RSM22BK black Regulator Drumhead is a single ply resonant bass head that features a small center-positioned Floating Muffling Ring for added resonant control. This Aquarian innovation eliminates the need for external muffling of the resonant head and 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. Furthermore the small 4.25-inch reinforced offset port is available in white and black video gloss and makes for easy mic placement while retaining optimum resonance.