Evans Rock Tom Pack (10", 12", 16") coated EC2 two-ply drum heads with Edge Control technology provide a pre-EQ sound via a damping technique that insures optimized performance for each individually sized drum head. Evans coated EC2 series features two plies of 7mil film with optimized attack, tone, length of sustain and ease of tuning for each size head. The Sound Shaping Technology (SST) Edge Control ring mounted on the underside delivers an extremely well balanced and pre-EQ'd sound across the full kit by varying the size of the ring for each different head size. Evans Level 360 technology is incorporated to extend the level playing surface of the drumhead, 360 degrees around the drum. The vertically enhanced collar design guarantees even contact with the critical bearing edge of the drum shell, resulting in: ease of tuning, extended pitch range and optimum quality of sound. Evans Level 360 technology resolves the age-old dilemma of traditional synthetic heads consistently not fitting the drum shell without using considerable force.