These helmets from Lazer fit sizes 46-52cm, which is 2cm smaller than the smallest helmet we had previously found, and several centimeters smaller than the smallest helmets found most places. The two centimeters difference between this helmet and the Airus (which starts at 48cm) may not seem like much, but if your child is 6-12 months (with an average sized head) the 48cm Airus will often fit too loose.  The extra room isn’t a big deal in the winter, because hats can be used to take up the extra space, but its deal-killer in hot summer months. Not only will these fit infants better than most helmets, they have a very nice micro adjust system (pictured below), the same found on many adult helmets. They also have a flat back so that they work better in child trailer than pointy helmets which push the child’s head uncomfortably forward.