The JerroStomp Repeater is basic echo/delay based on the PT2399 echo chip. The rate, decay, and dry/wet mix are all controllable with the 3 pots. Being analog the echo signal is a bit gritty, but not to the point of distortion like some basic echos.
The repeater runs on a standard 9 volt AC adapter with negative pin "Boss style" or 9 volt battery. This unit has a pretty good draw, so I'd recommend sticking with the AC adapter.
The knobs: Mix: goes from almost all dry (pre echo signal) to little dry and mostly wet (delayed) signal. Rate goes from too fast to hear to about a half a second, very approximately. Depth goes from 1 or 2 echos (or off) to oscillation, where the signal feeds on itself and grows out of control. Vary the rate while in oscillation and you get some really funky noises if you're into all that.