I think the neoprene grip grab gaiters are being discontinued. I had real trouble finding some for sensible money and ended up buying direct. Last pair I bought was from their official outlet on Amazon and were about £12. A lot of places that have stock are asking at least double that and I could bring myself to spend that much on something so basic.
They’re good, but they’re not going to totally seal your boots. If you’re riding long enough, you’ll still get wet feet. The important thing for me is keeping my feet warm even though they get wet.
Lake boots and merino socks work fairly well for me. Go for the thickest merino socks that you can fit inside your boots. Some grip grab gaiters over the top of the boots and then your waterproof bibs over the top of the gaiters. It’s probably as good as it’s going to get.
Where it looks like they’ve discontinued the neoprene ones, they’ve replaced them with a thinner, less stretchy but fully waterproof material. I bought some to try them out. No idea how well they work or how they compare to the neoprene because they were so small and unstretchy that I can’t even get them over my foot!