Revolutionary 4D GUIDANCE SYSTEM™ technology delivers adaptive stability when you need it most to keep you running longer.; FF BLAST™ PLUS ECO cushioning technology is extremely lightweight and provides shock absorption and responsive rebound.; FF BLAST™ PLUS ECO cushioning technology provides shock absorption upon impact.; OrthoLite™ X-55 sockliner enhances comfort with every stride.; Reflective details help increase visibility, especially in low-light areas.; AHARPLUS™ heel enhances outsole durability.; Flexible, technologically advanced knit fabric is used in the upper.; Redesigned external heel counter helps keep the foot in place and provides more comfortable strides.; The shoe's foam is bio-based and the mesh upper is made from 100% recycled polyester.; The shoe's sockliner also uses less water and carbon emissions to produce the shoe's insole.