The antenna must say Stalker dual DSR on the label. The early DSR's had white heads also and will probably work with the newer counter. I went from a Dual SL to a dual DSR and the antennas on the SL were not labeled DSR. I don't know if the Directitonal antenna will work in an SL but the 2x uses the same DSR antenna. The last antenna's I saw for sale without the counting unit were about 498 bucks a piece.