I have been buying and using Singh-Ray filters for decades.
Many years ago while on a photo trip in Yellowstone N.P., I had a Singh-Ray emergency. I needed to replace a graduated ND filter which I had damaged while shooting the Grand Prismatic Hot Springs. I called Singh- Ray on a Sunday from a coin pay phone near the Old Faithful Lodge where I was staying. Surprisingly, Bob Singh answered the phone himself. I explained my dilemma and he shipped to the Lodge a replacement filter which I received about 26 hours later.
Simply put, Singh-Ray makes the best photo/video filters on the planet.
Their customer service is top-shelf as well.