The RC-135M was an interim type with more limited ELINT capability than the RC-135C but with extensive additional COMINT capability. They were operated by the 82d Reconnaissance Squadron during the Vietnam War from Kadena AB, gathering signals intelligence over the Gulf of Tonkin and Laos with the program name Combat Apple (originally Burning Candy). [5] There were six RC-135M aircraft, 62-4131, 62-4132, 62-4134, 62-4135, 62-4138 and 62-4139, all of which were later modified to and continue in active serfvice as RC-135W Rivet Joints by the early 1980s.[6]