... ,calender and desk calender,album,office volume, etc. plastic single spiral coil 1.used for notebook ,bookbinding,calender and desk calender,album ... , etc.2. includes powder coated and nylon coated.3.Advantages:All colors are available according to different client's demand.High ... stable,uneasy to deform,rust.Specialities are customized. plastic single spiral coil for notebook