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.
(str1)