Features: 1.RES-consider this control as how big the room where the echo is, you will understand 2.CFR means tone control. LPF can add warmth to the effect, very practical and versatile 3.PRD set delay time, MIX set the amount of reverberation, DECAY set the length of the reverb 4.This overdrive pedal is very convenient for you to use, true bypass design minimizes tone loss 5.Aluminum alloy shell with higher strength, specific strength is close to high alloy steel, specific stiffness exceeds steel, possess good corrosion resistance, so the material of this product is very good specification:Item Type: Reverb Pedal Material: Aluminum alloy shell Power Requirements: 9V DC center negative(not include) Current Consumption: 50mA Product Size: Approx. 11.2 x 6.4 x 3.4cm / 4.4 x 2.5 x 1.3in PackageList: 1 x Reverb Pedal 1 x ReverbPedal Footpad 1 x User Manual NoteCustomers need to purchase an external power supply by yourself to be powered on