Singh-Ray Filters

I first came across Singh-Ray filters after reading an interview of an exceptional photographer by the name of Mike Dawson on Better Photo in 2008. I already had some neutral density filters form Hi-Tech, but the results weren't ideal for sunsets. Singh-ray are known for their high quality in the United States, but they aren't available in the UK. However, they make special reverse graduated neutral density filters, especially designed for sunsets and sunrises and are the only manufacturer that makes them that I'm aware of. Instead of having the darkest part of the filter at the top, the graduation is darkest at the centre, gradually decreasing towards the top, with the bottom remaining clear, as with a standard ND grad. I have been using them now for a year, with some results I'm really pleased with. In fact, with a couple of exceptions, most of my sunset work has been done using a 3 stop reverse grad. I've even been considering a 4 stop version, but I keep hoping the exchange rate will be more favourable first. I also usually couple it with a warming circular polarizer, instead of a slightly cool cast you get with most CPL filters, it warms the image up a little, again ideal for sunsets.
The filters have been instrumental in developing my style, without them my only option would be HDR, which is a technique I'm not over fond of, except as a tool for occasional use. They make it possible to make use of striking lighting, without resulting in blown highlights.