Arc-tested, adjustable sleeve straps designed by linemen. Fully arc tested - up to 40 cal with no melt, no drip. Self-Extinguishing: Comprised of all FR-Rated Materials. Arc Tested to ASTM F2621-19 standards: Up to 40 cal/cm² - No melt, no drip . Easily adjustable to fit your body type. Single-piece construction means no more lost buttons. Flexible design keeps you strapped in all day long. Made in the USA.