Made of hardened, galvanized, spring steel round wire. Safe to dry clean! Spiral steel boning offers flex on two axis... this makes it perfect for boning curved areas and areas where comfort and flexibility are most important. Use Boning Cutters to cut your lengths and apply Boning Tips to protect your fabrics from the cut edges. choose your width size and length size from drop down menu. 11 yard and up will come on a roll.