عدسات محدبة مستوية، زجاج بصري N-BK7*

These arrived well-packaged and the optical clarity is genuinely impressive for the price. I'm using them to collimate a laser beam and the focal length is spot-on for the parallel light work I needed.

The transmission on these is noticeably cleaner than the cheap uncoated lenses I was using before. I'm focusing a collimated diode down to a tight spot and the spherical surface gives me a clean, round focus with no visible scatter. Great value for N-BK7 at this price.

The edge is nicely beveled and the N-BK7 glass arrived completely free of chips or sleeks, which is more than I can say for my last order elsewhere. Collimating a laser with these was dead simple since the flat back sits flush against my mount.