The GM-35 is a 5" sealed-back paper cone midrange with a 3 oz. magnet. The specifications are: 40 watts RMS, 0.75" kapton voice coil, 8 ohm nominal impedance, frequency range: 600-15,000Hz, 97 dB @ 1W/1M. This midrange is a great match for the GT-25 paper dome tweeter.