SB Acoustics  Midwoofer is an excellent well known SB Acoustics Ferrite magnet 5" 8 ohm mid woofer, featuring a high efficiency low damping rubber surround. Used by several OEM manufacturers. Fitted with a proprietary composition coated paper cone, 1.2" voice coil. Very open cast frame for minimal reflections. Extended copper clad pole piece for lower distortion. Fs 41Hz, good level midrange response, a very flexible unit.