Hustler RM-40S -Hustler Super Resonators can handle 1 kW PEP and have slightly more bandwidth, especially on 40, 75, and 80 meters. Resonator whip adjustment allows for the fine tuning these efficient, mono-band, mobile antennas to the lowest SWR. Using the included Allen key, whip position is firmly set in the resonator whip tube with two 3/32 Allen set screws. These resonators complement Hustler mounts, mobile masts, and other accessories to custom-build your mobile antenna.