Created with the same attention to detail as their adult goggles, the Julbo Astro Kids' Goggle has a smaller shape designed to fight a youngster's face. Soft foam provides a comfortable cushion between the spherical lenses and your child's face, and the helmet-compatible shape plays nice with his or her safety lid. Julbo even worked in a clever venting system which keeps moisture from accumulating on the inside of the lenses and turning a fun day on the hill into a foggy mess.
According to Julbo web site, it's designed for kids ages 6 through 10. It fits my 5 yrs old daughter with plenty of room to grow. We are using Giro Slinghshot (size xs/s) helmet with this goggle and no fitting issues. We had pleasant experience with Julbo kids sunglasses and they did it again with kids goggle!