The Flex Loader is made by Thompson Center, although I should point out that all major muzzle loader manufacturers have their own version. They all perform about the same. It is a speed loader that holds three shots and four primers. The tubes are designed to hold three pellets and a bullet, but can be cut down if, like me, you only use two. The tubes are held in a soft rubber housing that has a lanyard hole. I tie it to my belt and have never had a tube come out, even in the thickest brush. I don’t think it would work well with powder, but I’ve never tried.
This speed loader is not the best on the market because it holds three rounds, or because it keeps primers handy (although those things are great). It is the best for one very simple design reason, the tubes only open on one end.
Traditional speed loaders open from either end. Do not ask me why. You have to remember, or look to see, which end holds the bullet and which end holds the pellets. I cannot tell you how many times, in the excitement of the hunt, I popped open the wrong end of one of the traditional speed loaders and loaded the bullet into my gun backwards. Of course, I never rammed the bullet down backwards, but it always got stuck in the barrel. This requires me to remove the breech plug and push it out with my ramrod. Very frustrating, especially when trying to make a follow up shot on a deer.
Everyone who has a muzzleloader and uses pellets should own and use a flex loader.
Score: 8/10
Smooth 
Ben