Prospect Quartz Saucony Endorphin Speed 3 Shoes. Size 7.5 women’s. Worn a few times (approx 20 miles) but like new. A reimagined S-curve winged nylon plate centers and supports your foot better for daily training. Updated geometry gives you as moother ride and more pop and spring for serious speed. A fully redesigned upper delivers a comfortable fit from heel to toe.