Why is the READY Helmet Light not built into the helmet?

The design of the READY Kids' Helmet is flexible, providing the option for the light to be added as an extra accessory to suit the individual child's requirements. The helmet light is also compatible with the READY Kids' Helmet in every size. In other words, you can keep using the same light even when your child needs to go up a size because they've outgrown their helmet. This means the light can be used for longer.