FKB110

The MB Quart FKB110 is a pair of 4-inch two-way coaxial speakers built to replace factory 4-inch speakers in car, truck, and SUV doors, dashes, and rear decks. Each speaker handles 40 W RMS and 80 W peak, for 80 W RMS and 160 W peak across the pair, so they work on factory radio power or a modest aftermarket amplifier. A 1-inch aluminum dome tweeter mounts at the center of the cone and reaches 19 kHz for clear highs, while the thermal-formed polypropylene cone stays light for quick midrange response. A 6 kHz internal crossover with a 12 dB slope hands frequencies from the midrange to the tweeter without an abrupt step. Butyl rubber surrounds add mid-bass depth and hold up to heat, cold, and humidity, and a high-temp adhesive bond between cone and surround keeps the two together during long high-volume sessions. A pure copper voice coil on a Kapton former builds a strong magnetic field and sheds heat, with an over-coil cooling path that moves air across the coil through the natural fiber spider. The progressive-die stamped steel frame stays rigid at full output, and a textured ABS gasket seals flat to the mounting surface to cut rattles and air leaks. Sensitivity of 88 dB means usable volume on low power. Fitment is simple: 3.69-inch cutout, 5.39-inch outside diameter, and 3-inch mounting depth, with spade or solder-direct connections.