size:no.8 teeth material: cupronickel tape material: neoprene item unit date width of zipper mm 7.0 total width of zipper mm 70.0 pulling intension of zipper n/in minimum250 strength of the top stop n minimum350 strength of the bottom stop n minimum350 airtight kpa minimum100 dive depth m minimum10 airtight after 200 times reciprocation kpa minimum90 dive depth after 200 times reciprprocation m minimum9 chain smooth n max55 smooth of top and bottom stop n max75 work temperature 　 -30℃-60℃ chemistry resist work safely after 24 hours deep in 93# gas