Ergodyne - EGO12123 Chill-Its 6255 Lightweight Phase Change Cooling Vest keeps workers cooler, safer and more productive. Pair with Chill-Its 6250 Cooling Packs (not included) that maintain a 64-degree Fahrenheit (18-degree Celsius) temperature for up to 2 hours when activated. Lightweight packs quickly recharge in as little as 5 minutes and feature a grid design that eliminates stiffness for more flexibility while you work. Made with a polyester cotton-blend fabric, the vest's adjustable, hook-and-loop closures around the waist provide a customized fit for different body types. Heavy-duty front zipper allows easy on/off. Two front zippered pockets can be used to store cell phones and other small accessories. This size fits chests 30.75" in diameter and has a 22.75" long center back.