Measured waist for a perfect fit. But when wrapped around the body, the clasp doesn't hold and they just fall off. You need to make sure you buy a belt that is much smaller than intended to get a good fit.
Pros
Universal design. The LEACOLKEY 3 Pack children's belt comes in three classic colors: black, brown and white, which makes it easy to combine with a variety of outfits. The slim elastic waistband also makes it easy to adjust the perfect fit for kids of all ages and sizes.
Cons
Durability Issues: Rubber can wear out much quicker than other materials with frequent use, so there's a risk these straps won't last as long as parents expect. Also, the plastic locking buckle may crack or break with frequent use.