Compatible with most blocks or bricks Includes 14 multi-color building blocks included 8-Bit inspired print graphics Recommended for kids 5-8 years old, but will fit most heads measuring 50-54cm. Always take a head measurement. Head sizes and shapes can vary, even within an age range. Using a helmet that doesn't fit can be dangerous. Complies with the U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 5 and Older. Also complies with U.S. ASTM Safety Standard for multi-impact Skateboard Helmets.