Vintage Analog Phaser pedal with Rate, Resonance and Depth Control.
The version of the BOSS PH-1 Phaser pedal but with the added "third knob" for resonance control - hence the "r" in the name.
Like the OG Phaser, PH-1, this is an analog 4 stage with an added Resonance control.
The original phase pedal (released 1977) was becuase of the popularity of the Leslie Speaker and guitar players using said speaker. These earlier phase pedals didn't exactly capture a Leslie but they did sound great and soon players found other sounds lurking in the sea of phase.
The resonance adjusts the feedback to add more depth/intensity to the phase sound creating some crazy effects!
This Consignment pedal is in Very Good+ condition with some cosmetic wear - as seen in the pictures.
The original black grommet/washer for the battery door has broken - as with a lot of old BOSS pedals.
NOTE this is another vintage BOSS pedal that takes ACA adapter (or equivalent) NOT the BOSS PSA adapter.