5# brass zipper 1 double sider 2 Nylon,plastic material can be waterproof 3 used for bags, boots,trunks 4 3#,5# 8 ... #,10# 5# brassqualifications: 1 we can make auto-lock slider,semi ... strength 3 slider against top stop4 pull pull of strength 5 pull twist of strength 6 reciprocation life (5000times ...