lifting clamps certificate:GS,CE,ISO9001,EN1492,EN12195 working load is up ... alloy. Loading range: 0 to 10 ton. Two pieces of clamps are used for the testing, but 2 pieces or 4 ... plate. Testing load is 2 times of working load.With lock spring during the clamp non-work condition, locking device going ... operating, over loading is prohibited.Durable enduring, easy operation. lifting clamps