Metric swivel hoist ring. The working load limit and recommended torque value are permanently stamped into each washer. Washer is color coded for easy identification: Silver - Metric thread. Individually Proof Tested to 2-1/2 times Working Load Limit. Bolt specification is a Grade 12.9 Alloy socket head cap screw to Din 912. All threads listed are metric (ASME/ANSI B18.3.1m). Designed to be used with ferrous workpiece only.