The Remo Clear Emperor SMT 20-inch Bass Drumhead (BB-1320-00-SMT) features a pre-muffled design with Sub Muffl Technology. It is constructed with 2-plies of 7-mil and 5-mil Clear film, and an externally mounted dampening profile with free-floating acoustic foam. It enables the head and drum shell to maintain full sound characteristics with additional attack and low-end frequencies. SMT technology allows a broad tonal spectrum of tuning ranges with controlled high and mid frequencies coupled with deep, powerful low tones. It is a new industry standard and one of the market's most musical and versatile pre-muffled bass drumheads. Ideal for live and recording applications.