OUTBACKER Heavy duty STAINLESS STEEL spring and BRASS base, combination. The antenna screws to top of the spring via the standard amateur thread size 3/8"x24 tpi. The chrome plated brass base mounts to the vehicle via a 1/2'' BSW bolt.(1/2"UNF USA) The Heavy duty Stainless steel spring screws onto the base, via a bsw thread. Conection from the transceiver to the spring base is via coax cable (optional) terminated with PL259 plugs. Costruction is of chrome plated brass and stainless steel spring.
NB: All Terlin Commercial Antenna have 1/2" BSW (whit) threaded springs.