BACK VENTILATION HOLES: Running belt hydration waist pack is designed with back ventilation holes, breathable and not stuffy. Anti slip and wear resistant. HEADPHONE HOLE: Running water waist pack is very comfortable and lightweight. Headphone hole on the front pocket allows you to enjoy your music easily. REFLECTIVE STRIP: Running belt hydration waist pouch is designed with an adjustable carabiner and a nighttime reflective strip for safer nighttime running. LARGE CAPACITY: Running waist pack has a larger zippered compartment for storing your cell phone, keys, MP3 and other multifunctional storage areas. 45 DEGREE BEVELED ANGLE: Running waist pouch features a fluent sliding zipper and clip for easy access to items. 45 degree angle for a snug fit.