Every detail of this heavy duty retractable key holder was built for rugged use and hard work. The extra durable polycarbonate case is impact resistant, and the tough Kevlar cord has been tested to over one million pulls, guaranteed to outlast any other retractable key holders on the market. The patented locking mechanism on the SuperRel Key Holder will ensure your keys, tools, and other items stay right at your hip without dropping to the ground.