Remo Powersonic Bass Drumheads are constructed of 2 ply 7-mil Mylar film, and has two internal, sub sonic dampening rings which enhance low end without adding hard-backed dampening materials to the drumhead. These drumheads also feature ESDS or External Snap-on Dampening System technology. Remo's unique patent pending ESDS system employs snaps mounted directly to the drumhead, which eliminates the possibility of vibration.