- Made of Superior Nickel Titanium Alloy for Engine Driven use. - Specially designed for the crown-down technique. - Offers a smooth and progressive enlargement of the canal. - Helix NiTi Rotary Files help to ease around curved canals and make a tapered preparation. - Helix NiTi Rotary Files use ISO Color identification and come in 21mm and 25mm lengths. - With amazing flexibility, easily move through canals, especially severely curved canals. - High resistance to cyclic fatigue and file separation. - Offers outstanding flexibility, cutting ability and reduce user fatigue. - Ergonomic handle provides comfort and excellent tactile feedback. - Recommended Speed: 150~350r/min