My toddler uses this vest every day. It allows her to swim forward easily yet prevents her from completely going under water.  The fit is a rather large range from 2 to 4 years but it works fine if I watch that I do not hold the shoulders too much and pull her up in it.  I do have to adjust the safety strap often to keep it from pulling too tight on her crotch but that is not a big deal. She loves this vest and swims 30 minutes to 1 hour every day with confidence.

My 3 year old daughter has been wanting to go swimming so we finally took her a couple of weeks ago.  She was excited to be in the water but also quite nervous. We decided to purchase a swim vest to increase her confidence and it works like a charm!

We had tried a few different vests that our friends used and were not too pleased.  Our daughter could barely stay upright in them.
We saw similar to this in a store but they did not have the right size so we ordered online.
The first time we put her in the pool it was like magic: she could bob up and down and also doggy paddle around the pool.  All of our friends' children love this vest too and now want to buy one as well.