We already had various massage tools and a couple of lacrosse balls for trigger point massage but when I saw this set I got it too. Then after using a day nabbed another set for my husband. The black 5鈥 ball is PERFECTION! It does what smaller lacrosse balls can鈥檛, gives you a broader roll but it鈥檚 quite firm so you can semi sit/lean on it for rolling on hip and buttocks. We use a foam roller for back of legs but sometimes it is too awkward and I am finding the black ball actually easier to use for tight hamstrings. Unexpected bonus was the red pokey ball, it is very hard and feels amazing to roll your feet across it.