Hit Air Vest Zipper Extension PanelWe truly enjoy these vest extender's when you just need a little more room to be comfortable and safe in you vest! The Hit Air Zipper Extension Panel can be used to adjust the fit of the Hit Air Advantage with Zipper Closure to ensure a perfect fit. Vest Model and Size specific, can only be used with the Hit Air Advantage with Zipper Closure Panel Width is 4 Vest Size Advantage XS S fits Advantage vest sizes X Small and Small Vest Size Advantage M XL