Neptio USA Flag Retro Athletic Side Split Short Sizing= Small: Waist 27-29", Medium: Waist 30- 32", Large: 32"-35", XL: Waist 36-39", XXL: 40-45".. Soft, Stretchy, Lightweight Nylon Elastane fabric Great for Running , Working Out or Swimming authentic Neptio Brand (Neptio is a registered trademark) Classic Side-Split retro style.