Vintage Mafco Nuclear Reactor Noise Detector Vibra-Tracer VT-101. Condition is very good. Comes in metal box 13 1/2" x  6 1/2" x 4 1/8". Inside is the Vibra- Tracer prob unit model VT101, the Coupler model VC-101, a set of "The Chief"  antique bakelite earphones and the hand typed instruction manual. The only reference I found in researching this item was that one was used to detect noises at a Nuclear Reactor by the U.S. ATOMIC ENERGY COMMISSION on the 1960s. Rare one of a one of an kind or very low low production item.