a few months back i emailed these guys to get some samples of the product and they had sent me a big envelope of some nice size pieces that seem to work well although i do not have a meter to measure the efficiency i though that for the price some of you may want to experiment
besides the normal rgb /cmy filter i got one was a UV pass filter that worked really nice depending on the light source (ie if it inherently has a lot of UV ) but it did pick off the UV line on my argon laser