JSP's EVO®5 DualSwitch™ is fully certified to both EN 397 and EN 12492, with the ability to change between the two standards easily at the flick of a switch. JSP have delivered an innovative helmet which can be used at ground level (EN 397) or at height (EN 12492). Working on the ground - Switch up - EN 397, EN 50365, ANSI / ISEA Z89.1. The chinstrap release force of EN 397 is between 15-25kg (approximately). This limits the risk of choking. The chinstrap has been designed to release if snagged. Working at height - Switch down - EN 12492, ANSI / ISEA Z89.1. The chinstrap release force of EN 12492 is greater than 50kg, (approximately). This limits the risk of losing the helmet during a fall.