SB34SWNRX-S75-6- Hard paper cone for improved piston operation (made in-house) - Vented pole piece for minimum compression - Vented cast aluminum chassis for optimum strength and low compression - 3 copper voice coil (4-layer) for improved power handling - Long life silver lead wires - Low damping medium hardness rubber surround for improved linearity and power handling - Non-conducting fiber glass voice coil former for minimum damping