Line 6 DL4 Stompbox Delay Modeler 3 programmable presets and on-board Tap Tempo True Bypass switching, so your direct tone is exactly that; direct from your guitar to your amp Expression Pedal Input - for real time control of all effect settings. 	Effect Selector, Delay Time, Repeats, Tweak, Tweez, Mix DL4 runs in discrete stereo, both inputs and outputs, so Left stays left and Right stays right. (Loop Sampler sums signal to mono) Runs from batteries or optional power adapter.