Smith Optics Forefront MIPS Adult MTB Cycling Helmet Aerocore construction featuring Koroyd: Koroyd material absorbs up to 30% more energy from an impact when tested to international standards Tubular core construction of Koroyd combines with EPS to create a system of Aerocore materials, which allow for a dramatic increase of air entering and exiting the helmet without compromising safety performance Koroyd is made from a polymer which can be recycled for use in future products