This listing is for a Rare and Hard to Find Defense Electronics Inc T-711-C RF Tuning Unit (Plug-in) for the TR-711 Telemetry Receiver. 284-410 MHz Previously used condition – Untested. Metal areas are tarnished like these were possibly silver plated? This is an item from a huge collection of vintage ham radio, test equipment, parts and camera equipment we are currently processing. We have many manuals, Ham Radios, thousands of test equipment and associated parts and pieces. The previous owner was a Ham Radio operator who collected all of these interesting items over the years. He really focused on purchasing equipment from special surplus auctions at the Nevada Test Site, Sandia Labs, Nellis Air Force Base, Kirtland Air force Base, etc. Many of the items we have are from EG&G, Department of Energy, NASA, Air Force, Navy, Marines and Army. The previous owner kept notes on nearly everything as it seemed to be his life-long hobby to collect, test, and document everything he owned. Manufacturing technology was not the same as it is today so imperfections should be expected. Also, these items may have been in storage for 40-80 years and could be dusty, greasy or have surface rust, spider webs, etc.