Check the listing for details. DIY Compressor Guitar Effects Pedal Handmade Finished Board !. Condition: New. Listed at 39.99 USD. Description : 1. Circuit board size: about 50mm * 56mm * 13mm, recommended 1590BB effector shell 2. Knob adjustment:Gain, Level,Compressor,Attack, 3. The circuit board uses a real bypass LED indicating circuit, which can use DPDT (double-pole double-throw switch, which is often called six-pin switch) or not use 3PDT (three-pole double-throw switch, which is often called nine-pin switch). The six-pin switch is smaller than the nine-pin switch, which can reduce the occupied space and make installation more convenient. When the switch is on, the LED is always on, and there is an effect output at this time. When the switch is turned off, the LED turns dark. 4. It is equipped with a nine-pin switch, which can be changed to a six-pin switch.