LUNDENG-Lima LIMAR149 children riding bicycles integrally molded helmet youth helmet Suitable for head circumference:M(50-57cm) Sleek, sculpted bike helmet ideal for commuting, touring, and cruising Tough polycarbonate outer shell and impact-absorbing EPA foam liner Single-size Universal Fit design; available in several hip colors Quick Lock Fit System Wind tunnel, duct design, effectively reduce wind resistance. Reasonable design, unique design, elegant, fashionable, comfortable breathable holes designed to wear with convenient. manufacturer lifetime warranty