南非采购需求：1.74光学镜片，变色（光学）镜片

I'm reaching out to inquire about the availability and pricing for 500 pieces of photochromic single vision lenses. I'm particularly interested in the semi design with a specific base and a high index for optimal performance. The size I need is 70mm, as it fits our product specifications perfectly. Could you provide details on the lead time for this order and any minimum order requirements? Additionally, if you have any samples or catalogues showcasing similar products, that would be helpful for our evaluation. Looking forward to your prompt response so we can proceed accordingly!