The new Evans EC2 SST (Sound Shaping Technology) heads use an ink ring that is painted onto the head rather than the glued on metal ring. The new ink ring allows Evans to control the ring thickness and density as well as the width. This allows them to really target select frequencies on each size and open up the tuning range. The character of each drum really comes out. These drumheads are replacing the current EC2 2-ply clear heads.