ASICS HEATFLAT FR 7 Track and Field Spikes ASICS HEATFLAT FR 7 Unisex Size: 23.5cm Spikes can only be used on the track. Includes spike pin covers. Please consider this item as used. HEATFLAT FR 7: With a stable flat heel structure, this model supports events from short and middle distances to hurdles and jumping events. SPEVAFOAM, which provides excellent resilience, is used throughout the midsole, and SOLYTE, which is lightweight, is used in the heel to reduce landing impact. The mesh area of the upper has been expanded to improve fit and breathability.