Using Heat-treated FireWire™ NiTi, the amazing flexibility found in the EdgeSEQUEL Sapphire will allow movement of 90° curves.EdgeSequel Sapphire™ has a triangular cross section with an open flute design and is a constant taper up to the cutting flutes (cutting flute length is 15 mm). Comes in .04 15-90 and .06 15-50 taper sizes and tips. Available in lengths 21mm, 25mm and 31mm with four same size files in each pack. EdgeSequel Sapphire will help elevate your technique and practice.