I was going to get one for my kid but most reviews said they did not work for heavier flows.

A lot of them have horrible chemicals in them so just watch out. I haven't tried them yet but I would like to to at least have extra protection I'd still have to wear a pad cuz my periods are crazy heavy. And yes I know most pads and tampons have tons of chemicals in them too but I buy the most organic cotton ones I can find and for what I go through I have to wear giant pads I can't wear the reusable stuff, I wish I could