Description If you are looking for professional optical lens, then your research is over here. That’s because our product can meet your need. Adopted of premium material, it is practical and durable for long time use. It is not easy to get deformed. Features -Color:Transparent -Material:PMMA -Size:4.20X4.20X0.75cm/1.65X1.65X0.29in -Diameter: 42mm -Center thickness: 7.5mm -With edge/edge thickness: 2.0mm -Focal length: 68mm -Object distance: 53mm -Magnification: 4.7 times -Light transmittance: above 93% -Temperature: -30℃+85℃ -Excellent for physics classroom demonstrations in optics and light refraction. -Also suitable for reading newspapers, books, magazines, maps, science, jewelry, inspection, rocks, handicrafts and so on. -Highly polished with ground edges, will not hurt your hands when use it. -There are sufficient quantities to meet your replacement and usage needs. -Made of premium and high-class material, which is durable and wear resistant. Excellent for physics classroom demonstrations in optics and light refraction. Also suitable for reading newspapers, books, magazines, maps, science, jewelry, inspection, rocks, handicrafts and so on. Highly polished with ground edges, will not hurt your hands when use it. There are sufficient quantities to meet your replacement and usage needs. Made of premium and high-class material, which is durable and wear resistant.