Hair Pins Staying Power The hairpin is composed of thicker, more advanced metal. Ball end design: less risk of injury to the scalp, more user-friendly. Beautiful lines, wavy root design, and tightening that holds. Bobby pins help you style your hair in an elegant and appealing way. Hair Pins for Women Style Wide Application The bobby pin's ridged side should rest against your scalp to ensure that both your hair and pin stay in place! However, if you use pins to style your hair, you slide them with the wavy side on top. Prior to using a pin.