Product Introduction Torsion Spring Features： Helical springs used to apply a torque or store rotational energy are commonly referred to as torsion springs. The ends of torsion springs are attached to other components, and when those components rotate around the center of the spring, the spring tries to push them back to their original position. Although the name implies otherwise, torsion springs are subjected to bending stress rather than torsional stress. They can store and release angular energy or statically hold a mechanism in place by deflecting the legs about the body centerline axis. This type of spring is normally close wound but can have pitch to reduce friction between the coils. They offer resistance to twist or rotationally applied force. Depending on the application, torsion springs can be designed to work in a clockwise or counter-clockwise rotation, thus determining the direction of the wind. 1. Easily placed any size archwire inside or outside mouth 2. Secure anchor for any auxiliary attachment 3. Bi-Directional hook for easy ligation 4. Smooth for patient comfort 5. Hight quality stainless steel 6. Size: 17*25 big middle and samll 7. packing: 10pcs/pack, total 1 pack.