Fresnel Lens Magnifier, Diameter 200mm (7.9''), Focal Length 200mm, Acrylic Lens (not Glass), for Physics Classroom, Solar Heating, Magnifiying, Fire Starter. (Focal Length 200mm)

Super happy with this lens! For my needs it was the perfect size and focal length. Well protected package with super fast shipping. Will definitely be buying a few more!

I used it to light a couple pieces of cardboard on fire it worked pretty well! But having to look at the bright blinding dot kind of sucks. Ive been trying to find something to fix that problem my sunglasses did not work. I want to try a pair of eclipse glasses.

Very nice. Gets stuff really hot.

Works great

You can't tell from the images, but it's not flat like other Fresnel Lenses I've used. It is covered in circular machining (?) ridges on one side. I'm guessing this design or poor machining is what results in the lens having a terrible focal point completely useless for starting fires on tinder. I would give it 1 star but am assuming amazon lied to me in my search and/or there are variations in Fresnel Lenses that I am unaware of.They've since updated their images to show the ridging. Apparently it is a valid design. With that said, I could not get it to focus how the pictures showed with clear sun overhead. For comparison, my wallet sized Fresnel Lens produced a better focal point so the 3 stars stand.