goo.gl/zlWjB1
I've wanted to get a pair of these for the longest time and just forgot about them until I accepted with the recently posted-about job requiring me to rip over 50 sheets of 1/2" plywood and even further cutting to size on the tablesaw.
I found that Woodcraft either bought them out or have licensed the product under their home brand "WoodRiver." These are identical in every way to the ones I saw on other suppliers' websites and catalogs.
The only hesitation I had were some bad reviews on Woodcraft's website claiming they switched the materials that the rollers were made from, making them "slippery." I haven't found that to be true, so far. Here they are installed.
This is another product I purchased and used which gave me the immediate feeling of, "Why didn't I get these years ago?" Such a simple addition to the saw that really improves overall performance. It's much easier to guide to stock against and along the fence. These are so much easier to use than a vertical featherboard and are pretty self-adjusting once you quickly get them "in the ballpark" with the adjustment eye-bolt.
I'm very pleased, so far, and highly recommend them. They can be had for cheaper on Amazon if you don't need them "today" like I did.