1 nylon fine coated spiral coils 2 envirmental friendly 3 a wide color for choice 4 RoHS and ASTM certificate; SGS test 1, metal spiral coils are made of high quality nylon coated wire2, it is in free per-cut 3, there are various colors for your choices4, metal spiral coils is the ideal binding material for book binding and calendar bindings5, can be supplied loose in carton or 100pcs per bundle. ...