The five Delay Select buttons switch between delay times ranging from 2.5 to 160 m/sec and the Delay Variation knob allows more precise fine-tuning.In addition to a straight delay, there's great thick doubling effects; with modulation you can create flanging effects, Feedback, Modulation Frequency and Modulation Depth knobs for additional sounds. You can control modulation via CV input, and there's also balanced XLR input. This is a modified unit with a 1/4" input on the face and two added selector switches