This is a large (135mm diameter approx) lens designed for lazer projectors. Optimized for 535nm wavelength but admits normal daylight with just a minor yellow tint. Mounted onto a sinar lens panel and was used for extreme bokeh closeup photography but you could use it for light shaping too. Has a significant scratch on the front but this has no affect on the image across such a big piece of glass. A great experimenters tool.