The purposeful flat back design allows for your little rider to sit comfortably in a child carrier or trailer. The exposed foam on the rear of the helmet helps dampen bumps against the seat.This bike helmet has a sleek, easy-to-use dial fit system that offers an adjustable, secure fit with a quick turn of the dial.Recommended for kids 1–3 years old with heads measuring 48–52 cm.3D Flexible Shark Fin,3D Flexible Unicorn Horn & Mane,Adjustable Straps,CPSC & ASTM Certified,Impact Liner Type - Expanded Polstyrene Foam,Shell Type - PVC Shell,Ventilation Type - Aerodynamic Cooling Vents,Size - Infant, Unisize 48-52cm.