I bought this helmet in the summer for my 18 month old daughter as my husband and I wanted to take her cycling on the back of our bikes. I spent ages trying to find a helmet that would fit her small head, and after measuring her head came across this one on Amazon. The structure of the helmet is great - lightweight and sturdy with an adjustable headband inside and chin straps (standard helmet fittings). Design-wise, the one I chose was white with pink flowers which looks nice on my daughter (not that she cares how it looks!).
I would recommend this helmet if you have a young child or one with a small head, and there are plenty of designs to choose from which is a bonus.