The RG series of pickups is specifically designed to fit "dobro" style spider bridge resonator guitars. For biscuit bridge guitars, use the Schatten NR series pickups. For tricone resonator guitars, use the Schatten TC series pickups. Schatten has produced a resonator guitar pickup that met their exacting standards for faithful sound reproduction, ease of installation, great anti-feedback characteristics, and so much more. Innovative Design Until Schatten designed the RG-03, all resonator pickups were either stuck onto the side of the cone (which invariably caused feedback issues) or else required the replacement of large parts of the resonator assembly (not to mention a lot of expense and probable modification to the instrument). There also were some magnetic pickups that were meant to fit under the strings at the end of the fingerboard - but these were never particularly acoustic sounding. The design of the RG-03 mounts the piezo element directly on center on the underside of the resonator cone on 'Dobro' style single-cone instruments. This placement of the piezo unit is the best for sound and the best for feedback resistance. Schatten knows this because it is their design. Their competitors know this as well because in bringing out their own reso pickup, they copied most of Schatten's. Players who will be plugging directly into a 'normal' guitar amp will find that they get great sound quality from the RG-03 in passive form. No preamp should be required in this situation. Players who must plug directly into a mixing board will most likely need to preamp their signal in order to match up with what most mixers require in terms of impedance and signal strength. If you wish to have the electronics and battery on board the instrument then you should be purchasing the 'A' or Active model of the RG-03 that includes the Artist II preamp, which can be externally powered, or use the external Schatten Preamp/DI.