I bought these Blue Rehband knee supports only a few days before Rogue started carrying them. It's a shame since I could have used the "3 Ships Free" promotion. Prior to this, there were only a few places on the internet where you could get the original blue versions. The difference between the blue and the grey is the thickness of the neoprene. These originals are 7mm while the grey "newer" model is 5mm. For me, I feel that the blue ones provide more support especially when I'm in the absolute bottom (ATG) of my back squat, cleans, or snatches. Some people will like the grey ones better, it all depends on personal preference. When wearing these supports, my knees warm up quicker and require less warm up sets before I feel my knee joints are properly warmed up and lubricated. I also feel that it helps me pull under the bar faster in cleans/snatches since I'm less worried about my knees. As with the grey rehbands, you'll want to size down. I measured as a medium, but went with a small. This size worked well for me.