Features: 1) Types available: 3#, 4#, 5#, 7#, 8#, 10# 2) More specifications available 3) The smooth teeth can bear the corrosion of alkali, acid and oxidation 4) Reinforcing tape fits well without breaking or coming off Test result: 1)Breaking strength of chain : 450.8N 2)Slider locking : 88.2 N 3)Puller attachment : 274.4 4)Repeated extension 5000 times without any dilapidation.