Review on Ajax Scientific 🔍 Bi-Convex Spherical Double Lens by Jose Guevara

I bought this lens to use as a fire starter in the woods and it does a great job. I had a small hot spot on the dry grass after a few seconds once I got the focal length right. It seems to perform as well or even better than plastic Fresnel lenses (and doesn't bend or crack over time), although I haven't tested it directly. This is a small heavy glass lens. Mine came with no scratches or stains, was well wrapped in bubble wrap.