K-Files 21mm #55 6/Box. Stainless Steel. K-File is manufactured from high-quality 18/8 German stainless steel for reinforced flexibility and precision for ordinary root canal procedures. Each K-File has a pre-mounted silicon stop and a ribbed-textured, peanut-shaped handle for enhanced grip and tactile feel for better control during use.Handles are color-coded for convenient # identification. The safety eye feature promotes easy threading for added protection.Available in 21.0 mm, 25 mm, or 31.0 mm, in 6 files per pack.