The Joyo JF-19 features a buffer and tuner. The Buffer solves the problem of long audio cables or tone loss due to several pedals being connected in series, while the Buffer circuit preserves the original tone when using several pedals. It is suitable for 7-string guitars and basses thanks to its super-fast response and high-precision tuning algorithm, tuning accuracy: +/- 1 cent, the real-time LED display allows you to read it clearly in dark stage environments. DC 9V output connector (center negative). In addition, you can choose between True Bypass mode and True Buffer mode via the selector switch.