Check the listing for details. Evans EMAD Heavyweight Clear Batter Bass Drum Head 24 in.. Condition: New. Listed at 64.99 USD. The EMAD Heavyweight clear batter bass drum head features two plies of film. The combination of two identical plies of 10-mil film provides maximum durability and a compressed attack while maintaining a wide dynamic range. The EMAD Heavyweight contains two interchangeable damping rings that maximize attack and low end without removing the head or reaching inside the drum. The industry-standard Externally Mounted Adjustable Damping (EMAD) system allows the player to adjust attack and focus.