The Performance II is a two-ply drumhead manufactured using Aquarian’s vacuum-fit process that eliminates air bubbles and wrinkles between plies. The two clear 7 mil plies are glued and sealed only on the edges and control unwanted overtones while focusing on the low frequencies. These heads are designed for loose tunings and deliver that low, thick, punchy tom-tom sound that was a big part of classic rock and roll records. The Frequency Control that adds focused power is built into this head. The PFII is a great head to immediately upgrade and improve the sound of low-priced kits. 2 plies of clear 7 mil film Thick, low frequency response with control Made for loose tunings