Fresnel Lens, Diameter 100mm (4''), Focal Length 50mm, Acrylic Lens (not Glass), for Physics Classroom, Solar Heating, Magnifiying. (Focal Length 50mm)

Ants and small piles of dry brush beware. Works as expected for lighting up char cloth or tinder. Need to find a decent hard case for packing in a bag so it does not get smashed around.

Extremely happy with the purchase. Very well make. Than Q

Focused light correctly Lightweight and easy to use. Its plastic so it will scratch easily

It is small and very thin. The lens is directional. You must look through the proper side or the perifery will be distorted and pin point heat will not be there. When looking through it the proper direction it is good for its size. It will start a fire under ideal conditions. Anything larger than this item might be considered dangerous as the heat would be very high. I saw a 10" magnifying glass years ago and it would start things on fire quickly.

Purchased for emergency fire starter. Good quality, compact yet functional. Shows easily and works great for my needs.

Its plastic and not suitable for hot lamps

I figured it would be a great product but being that it's plastic and not actual glass it's a big difference and for me I prefer glass

Works for what it is not the best not the worst

Right size. Popped right into my lamp and works just fine