Petzl Harness Simba
It's Petzl, quality is always top notch. And the lil cartoons on the straps are a nice touch with the kids. But lets talk fit for the lil ones. We have twins who are 40 lbs and 4 years old and a 6 year old at about 60 lbs. Our use is mostly for our zip line. To make the zip line as independent for them as possible we have kept it low enough that they can reach the ground through half of its travel, at most their feet are about 2 feet off the ground. 30 ft long in total, so there's about 15 feet at least where all 3 can go crazy, pretend to fly, spin around in circles, bounce up and down. One kid even tried to bend over backwards by tossing his feet on the line once it stopped. In all cases they were never able to squirm or wiggle it into a position where it was not fitting properly or chaffing. Our kids are some what skinny too. Always, back to the safe 'seated' position of a harness.