it is made of 100% polyester yarn that has high tensile strength,high resistance to ... salt,heat and abrasion SpecificationsBag closing thread is made of 100% polyester yarn that has high tensile strength,high resistance to alkali ... , etc Standard Specification: - NE 20/6 ply, NE 12/4 ply, NE 12/5 ply, NE 10/5 ply, etc ... , pls feel free to contact us for more details. 100% polyester bag closing thread