This is a good product for helping skinny little kids flutter kick with straight legs.  However, if a kid is larger, it does not fit.  I wish Speedo would make these in small, medium, and large sizes.

Excellent tool for young swimmers.  Prevents the bicycle kick so you can begin to teach correct leg position

This really works to help young kids who struggle with poor kicking.  Although it is recommended for kids 2-10, it does not fit young kids with big legs.  I have had swimmers within the age stated that it just does not fit.