Under ArmourWomen's UA W Charged Surge 4, Ultra-Responsive Running Shoes for Women, Lightweight and Breathable Gym Shoes, Women's Trainers with Charged Cushioning

Very comfortable. I have quite narrow feet and a lot of shoes hurt and rub the back of my feet but these felt amazing when I first put them on, and never hurt. One thing - at the end of the day if you've been wearing them all day (which perhaps I shouldn't) they get slightly tight. But ideal for running with!