The PT-909 is known for its warm, rich, and subtle four-stage analog phasing, which adds depth and movement to the guitar tone without being overly aggressive or "in-your-face" Speed: Adjusts the rate (speed) of the phase effect. Width: Controls the amount or intensity of the phase shift. Feedback: Determines the amount of the effected signal fed back into the circuit, adding a more pronounced "swooshy" or "vortex" quality when increased. Power: It operates on a 9V DC power supply (3.5mm, center positive jack) or a 9V battery. Collectibility: Due to its high-quality Japanese craftsmanship and association with the iconic Ibanez 9-series, it is considered a collector's item and is often sought after in the vintage effects market.