Close coil spring. Features: - Designed to close or maintain space with stainless steel eyelet for easy attachment. - Delivers constant force levels. - Active until the spring is closed. - Provides comfortable, predictable forces during treatment. Specifications: - Super elastic Nickel Titanium quality. - Stainless steel key-end eyelets for easy attachment. - Medium force. - Diameter: 0.010 inch. - Length: 6 mm.