I use the Tykma Electrox BOQX 20 W MOPA laser for engraving the bottom of the Joulescope JS220.
My contract manufacturer required a reputable class 1 laser system. After much investigation and discussion with them, we agreed that the BOQX check all the boxes 
It looks like the BOQX is no longer on the website…
The JS220 enclosure is sandblasted, black anodized aluminum, and I really like the look of the white MOPA laser marking. The engraving takes about 1 minute per unit.
We have been using this for over three years for relatively small volume production, and it has been great. We did spend some time tweaking the settings and adding another pass. A later batch of enclosures arrived with a thicker anodizing, which required a bit more laser time to get a nice finish.
Also see this topic Laser marking for small-volume production, and this direct link to see it in action