This simple yet profound phaser effect creates a deep sound. The Phase 90, which appeared in the 1970s, is known for its simplicity with an orange casing and a single speed knob, and was famously used by Van Halen. https://en.wikipedia.org/wiki/MXR_Phase_90#:~:text=The%20Phase%2090%20was%20the,2. It adds depth to guitar arpeggios and leads, and is perfect for rock and funk. I was using this until recently, and I've performed a basic operational check. Knowledge is required for use and installation. No claims and no returns accepted. Please see the photos for the product's condition. This is a used item, so please refrain from bidding if you are extremely sensitive to condition or are looking for a new-like condition. We will ship within 2-4 days after the bid. Management number: 26