The BOB is designed to be one size fits all. The Comfit3 Fit System is easy to adjust, and its wide size range means that it will fit your child for longer as they grow. Thick and soft padding makes the helmet ultra-comfortable. The BOB is designed especially for use on child seats and trailers. The rear of the helmet is flat, so that your child can comfortably rest their head on the back of the seat. Reflective stickers increase your visibility in low light.