KOKKO FLP2 Mini SOS Looper Guitar Loop Recording Monoblock Effects Pedal, FLP21. High quality by aluminum alloy which is durable and have a classic mini size brings you a musical feast. 2. Use this knob to control the volume level for the loop playback. 3. One knob cover record, overdub, undo the loop,redo the loop, erasing, and store the current loop function. 4. LED indicator shows the status of effect. 5. No battery, powered by AC adapter(not included). Specification: General Model FLP2 Material Aluminum Size 90*40*33mm