● forged from high strength and high toughness special alloy steel and heat treated

● each piece shall be verified and tested according to 2.5 times of the working tension

● sample 20000 fatigue tests

● carry out strict sampling breaking test for each batch of products

● 100% magnetic particle inspection

● it can be combined with en818-2 Grade 80 chain

● four times safety factor

● surface treatment: plastic spraying