CNCOLETECH CO2 Laser Lens Dia:15mm FL:2 or 50.8mm Laser Mirror CVD ZnSe Focus Focal Lens for CO2 Laser Engraving Cutting Engraver/Cutter 40W-200W

k40 lasted 2 hours crap

Very well packed. Outside plastic bag, then a box with foam, then a smaller plastic bag on the box and then the lens wrapped in tissue

smaller than others I have ordered but still worked

Helps to focus

works great

Yeah this is not 12mm and therefore unusable junk.

Good

Replaced original lens in 40w laser cutter and was able to use less power to cut through wood.

Yeah this is not 12mm and therefore unusable junk.

used these 4 100s of hours on a 50 wt , work great