1）What are the advantages of PC lenses? ①High impact material is safer to the energetic children Perfect protection to the eyes ②Thin thickness, lightweight, light burden to children's nose bridge ③Suitable to all groups, especially the children and sportsmen ④Light and thin edge offer aesthetical appeal ⑤Suitable for all kinds of frames, especially rimless and half-rimless frames ⑥Block harmful UV lights and solar rays ⑦Good choice to those who do a lot of outdoor activities ⑧Good choice to those who love sports ⑨Break resistant and high-impact2）What is photochromic lens？ Photochromic lenses are also known as “photosensitive lenses”. According to the principle of reversible reaction of light color alternation, the lens can quickly darken under light and ultraviolet radiation, block strong light and absorb ultraviolet light, and show neutral absorption to visible light. Back to dark, can quickly restore colorless transparent state, ensure the lens transmittance. So the color changing lens is suitable for indoor and outdoor use at the same time, to prevent sunlight, ultraviolet light, glare on the eye damage.Photochromic lenses are also known as “photosensitive lenses”. According to the principle of reversible reaction of light color alternation, the lens can quickly darken under light and ultraviolet radiation, block strong light and absorb ultraviolet light, and show neutral absorption to visible light. Back to dark, can quickly restore colorless transparent state, ensure the lens transmittance. So the color changing lens is suitable for indoor and outdoor use at the same time, to prevent sunlight, ultraviolet light, glare on the eye damage. 
3. What is the difference between HC, HMC and SHC？
| Hard coating | AR coating/Hard multi coating | Super hydrophobic coating |
| makes the uncoated lens hard and increases the abrasion resistance | increases the transmittance of the lens and reduces surface reflections | makes the lens waterproof, antistatic, anti slip and oil resistance |
| 1.59 Photochromic polycarbonate lens | |
| Model: | 1.59 optical lens |
| Place of Origin: | Jiangsu, China |
| Brand: | SETO |
| Lenses Material: | Resin |
| Function | Photochromic & Polycarbonate |
| Lenses Color | Grey |
| Refractive Index: | 1.59 |
| Diameter: | 65/70 mm |
| Abbe Value: | 33 |
| Specific Gravity: | 1.20 |
| Coating Choice: | HMC/SHMC |
| Coating color | Green |
| Power Range: | Sph: 0.00 ~-8.00;+0.25~+6.00 CYL: 0~ -6.00 |