I love this product! My husband was hesitant about using a child leash, because he felt like it would be dehumanizing, but I was worried about our toddler's safety. This item is the best of both worlds. It lets us keep her close to us when we're out, but the strap is long enough that she doesn't feel restricted. Also, she loves wearing it! She really enjoys putting on her backpack when we're going out, and picking out a toy to put inside and bring along. Not only is it not dehumanizing as other child leashes can be, but it even seems to make her feel more independent and confident.
I got this for my daughter when she was 15 months old, and it fit her well when we tightened all the adjustable straps. The backpack isn't heavy at all, so it isn't putting any stress on her back to wear it.