What is the exact focus point of 40W laser module from the tip of the tuyere to the work surface?

Artisan (3-in-1)
1

What is the exact focus point of 40W laser module from the tip of the tuyere to the work surface?
I know they say it is fixed focus, but I would like to know what that number (distance) is.

2

Fixed focus distance is 7mm from tip to material.