4FR ferrite based mid-woofer was developed for applications where small size mid-woofer is required. Low resonant frequency and large cone excursion delivers seizable amounts of low frequencies. Yet, this driver delivers very good performance in mid-high frequency range. Our engineers have chosen lightweight, yet strong, paper cone with rubber surround. Cone optimized shape brings remarkable strength of the piston and greatly improves harmonic distortion artifacts. Overall this model delivers very good performance and is well balanced between performance - cost.