Radio Shack produced the Realistic Mach One speaker for almost ten years, beginning in the 1970s. The Mach One 15" 3-way system is considered one of the finest loudspeakers offered by Radio Shack. Over time, many Mach Ones have been lost due to foam rot and old age. We've produced a 15" driver that features the same warm, thundering sound characteristics as the original, but thanks to contemporary materials and technology will last far longer. Now you can resurrect your set of Realistic Mach One speakers with completely new woofers, giving them a fresh lease on life! Replaces Realistic Mach One, Mach Two, 3802, 40-4029, 40-4032, 40-4032A, Optimus Pro 4000. Note: This unit is an exact replica of the Mach One. The Mach Two is slightly different, but this unit works great for them too!