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

● 25% higher than the strength of Grade 80 chain double ring buckle

● 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

● can be combined with class 100 chain

● four times safety factor

● surface treatment: plastic spraying