This is the backtrack. It's different than other foam rollers because of the density. It's made out of a foam, it's flexible, and it has a special groove in it. A lot of the other rolls are painful to do myofascial release, but this has got a different purpose on the spine. The vertebrae have a spinus and this groove allows that spine just to float it. Doesn't crunch it or push it, but the edges, this is called the transfers process. It catches them. So it's like a train on a train track. You will hear your back pop and crack, and you pretty much lay down and you can see for the top view of how these bones are catching the edge, and you're just gonna roll it. And you can even roll clear up in your shoulder blades. You know, as far as you can go, because the groove accommodates all sides of your Birdbrain and your back and not just every one of these joints, cause some stretch to it. And then your nerves come out of a sheath called a meningioma, and those can get pinched. So when you run on this thing, it is flexing and stretching every joint and allowing nerve impulses to go out. These besides working out tightness and alignment issues. And these come in two different densities, this is the medium, and then we have a heart. And what that does is if you're injured and have pain in your back, you would want to start with this enrolling and then work up to the harder one. And there's people that are muscular athletic. They're going to need the harder one because you know, some people's joints stretch and pop easily and other ones don't. So if you're, you know, really, really tight. You're going to need this as well until we can start giving some flex and flexibility into your spine. But this is a called the backtrack and it's, something that you can clean off. Cause it's got a smooth surface and you can use it multiple times a day or before you exercise or afterwards.