The Master Bypass switch is intended for Loopers with 2 or more loops. It is quite difficult to switch more than 2 switches fast and safe while playing your instrument. The Master Bypass switch is doing that for you with one click. The Master Bypass mode is displayed by a status LED.
The kit contains everything you need to build it. It is only intended to be used as an addon to an existing effect or switcher.
Wiring layout: Wiring