Evans EMTP-SB1 System Blue Drumhead Tenor Pack - 6in, 10in, 12in, 13in & 14inEVANS System Blue Marching Tenor Series was developed with the Blue Devils, the DCI World Championship winners. Incorporated with EVANS Level 360 Technology for ease of tuning, extended pitch range, and optimum quality of sound, this drumhead features a unique film and sound control technique which provides enhanced attack, tonal clarity, and projection with increased durability and tuning stability. Features Made with 7mil and 7. 5mil films. Advanced