I bought these for my son and daughter. Both are 7, weigh 50 - 60 lbs, and had been using gym harnesses for the last month. These are a big step up in comfort and simplicity, and there's a lot of room for them to grow. I've hung both of them upside down, with not issues beyond their mom giving me the stink eye. My son is convinced that he can climb higher because of this harness, although his sister is still climbing much higher than him (he's the stronger climber, but she's gutsier).The bottom line is that these are really nice harnesses, and when the kids outgrow them, they'll be ready for adult harnesses.