The Evans EC2 Coated Drumhead with SST is a two-ply head with 7mil each, with Sound Shaping Technology mounted underneath. By controlling edge vibration (instead of eliminating it), the ring isolates and damps higher overtones, enhancing low-end and attack, and enabling a broader tuning range with the EC2 Coated Drumhead with SST. Expect great durability, punch, and focus with this Coated version of the Evans EC2 with SST.