This is a high power blue fiber coupled laser,the output power is 4000mW,and it can be adjustable. The adjustor is for changing the current thus laser power. The current value is showed on the panel. The knob should be tuned gently and smoothly. You can lock the knob by the push switch on side of the knob.
Laser link: https://www.civillaser.com/index.php?main_page=product_info&products_id=710
