The Checklink Wheel Nut Indicator and Retainer from Martins Industries is a dual-purpose wheel nut indicator and retainer. The Checklink both indicates and retains against unwanted wheel nut movement as well as indicates any overheating of wheels caused by faulty brakes or bearings as it will melt at specific temperatures (257 degrees F). Connecting two adjacent wheel nuts with the Checklink’s distinctive ‘S’ shape provides a retaining function, causing resistance to the loosening of wheel nuts. If the wheel nut still manages to loosen, this will be indicated by the distortion of ‘S’ shape. Made of high-grade virgin polymer to ensure product quality and performance reliability for overheating indication. Available in bags of 50pcs; multiple colors and sizes available.