Powerstroke Pro Bass Drumhead. Constructed with 10 mil film, the Powerstroke Pro features Pressure Dampening Profile and permanently mounted acoustic foam that provides maximum volume and projection while producing controlled highs, accentuated mid and maximum low range frequencies. The Ultrasonically Welded Profile alleviates separation and unwanted noise, making it ideal for live and studio use. Powerstroke Pro is the new standard in subsonic bass drumheads delivering unmatched sound, feel and performance. Diameter: 20", suitable for: Bass, Series: Powerstroke Pro, Finish: Coated