Globber helmet Go Up Lights XS / XXS 45 to 51 cm. The tested Globber children's helmet impresses with its simple, trendy shape and light weight. The ventilation slots help all riders to keep a cool head, even in tricky situations. The in-mould construction of the helmet makes the Globber helmet one of the "lightweights" among urban helmets, without neglecting quality and safety. Globber helmets have a very good fit and are very comfortable to wear. The LED light with button battery at the back of the helmet ensures high visibility even in poor light conditions. How do I measure the head circumference?