Can be crimped to any rectangular wire from .016x.025 allowing you to secure an anchor for any auxiliary attachment. Ultimate hooks crimp to rectangular wire from .016x.022 to .019 x.025. Place the ultimate hook on the arch wire using hook crimping plier or a hard wire cutter and apply pressure. If placement is made with a hard wire cutter apply pressure on the mesial and distal side of the hook. Short hooks must be placed with a hard wire cutter. **For further product information, please contact Chat Support**