YoraHome 6550 User Manual page 34

Part 3
Software Introduction - LaserGRBL
If your machine is equipped with either the 3.5W or 5.5W lasers, the lens
5.
must be focused at the appropriate focal height of 45mm. Click the "Focus"
button at the bottom of the program window to turn the laser on at low
power for focusing, click again to turn the laser off.
Note that your screen may have a different appearance or label, depending
upon program version installed.