Pair vintage Radio Shack 4 inch midrange speakers in mostly good state. Ferrofluid cooled with 92dB SPL (I Think.) Good to use in first order crossover systems where a separate chamber for the midrange is not required. L-pads are recommended in order to adjust speaker output to rest of system. Operates at 1.5Khz to 11Khz frequencies. For hobbyists or experimenters in audio sound systems. Original boxes the midranges  came in are included as well as one pamphlet that came with the speakers.