This is the Clansman PRC-319 Antenna Tuner Unit RF TURF. Extender Manufactured by MEL Type No. BA1305. It is used to extend the tuning range of the PRC-319 TURF and match the transmitting frequency of the PRC-319 to the antenna to give optimum performance and achieve maximum range with the radio set. To tune the antenna it digitally talks to the radio through the 7 pin connector to the TURF. NSN: 5820-99-734-7837. Supplied in good condition.