Run Small: Features a snug, shallow design that may sit higher on the ears depending on individual fit. Nike hats, including beanies and select cap styles, are made in one size. This one-size design generally fits customers who wear fitted hat sizes ranging from 6 1/2 to 7 3/4. Therma-FIT Warmth and Lightweight Comfort: Advanced fabric traps body heat while soft, breathable fleece insulates without adding bulk, keeping you comfortably warm in cold conditions.