Hello Sir or Madam:Located in Danyang city of China, my factory specailizes in making high quality finished and semifinished lenses of 1) CR-39 S.V. and bifocals, 2) CR-39 progressive, 3) 1.56 photochromic for years.Good quality at a lower price with quickly delivery time is offered.Pls feel free to contact us for a cooperation !Thank you ! Simon Zhao - Email: *****Lotus Optic