Available from Laser Research Optics is a line of field-replaceable lenses and turning mirrors for the lower-power laser systems that are used for engraving and marking wood, plastics and light metals. Optimized for 10.6 μm, where depth of field is critical, they provide <0.2% total absorption. The drop-in lenses and mirrors are available in diameter sizes from 1/2 to 1 1/2 in. and offered with focal lengths from 1 to 25 in. in 1/2-in. increments. They feature 40-20 scratch-dig surface quality, and they meet OEM and ISO-10110 specifications.