Metal spiral binding wire 1.nylon coated wire. 2.form iron single coil. 3.smooth surface. 4.various color. Metal spiral binding wire. With environmental sgs testing:. Nylon coated,smooth and lustrous surface,strong adhesiveness,endure abrasion and humidity,be able to bear rusting ,eroding,and aging. Made of ... . Innocuous made of ... ,which complies with the environmental safty standards of occident. Pull:. Stonge pull,stable shape and quality,low wastage. Specification:. 1/4"(6.4mm)----2"(50.8mm). Range:. Notebook,album,calendar and so on.