Attached narrow felt muffle ring moves and "breathes" with the drumhead and reduces annoying overtones while enhancing the low-end frequencies with a well-defined punchy sound. Aquarian’s “multi-ply vacuum molding process” makes the two 7mil plies act as one-ply to add punch, clarity, and a pure tone. The durable SKII creates just the right balance between resonance control and a “big bass drum sound.