1.IN interface:A 6.35mm(1/4inch) mono interface connects to a guitar or other instrument 2.OUT/PHONES connection:6.35mm(1/4inch ) TRS stereo unbalanced output interface compatible with headphone output. When you need to connect a mono device such as a guitar speaker or a single block, use to connect the local output. 3.VOL knob:Controls the total output volume of the GP-5. 4.PARA knob (with buttons): Under the main interface, turn the knob to switch the preset, the knob to enter the global setting interface, and long the knob to switch the BT wireless function. 5.LCD display:The full-color LCD display shows the GP-5's preset number, name, and other operational information. Color: As Shown Material: Metal Package Contents: 1 x Guitar Effect Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.