Western manufacturers of laser engravers typically offer a single, very high priced, focus lens and holder, such as Epilog Laser, ULS, Trotec, and Xenetech.  Bell Laser offers two choices, a premium grade similar, if not the same, as the manufacturer sells, and medium grade, or a step down in quality with a big savings. As laser engraver owners recognize that not all customer jobs are the same, they tend to purchase both types, and more focal lengths to expand capability, because of the new affordability of our lens plus holder products.  Further, we also supply the manual focus tools as well, including manual and plunger.