Dental Root Canal File Counting Disinfection Box Autoclave Sterilizer Case Burs Endo Files Holder With Count There are a total of 12 knobs on the upper and lower outer sides, one color. Low-risk area, suitable for straight root canals of anterior or posterior teeth. The 6 knobs in the middle，two colors，high risk area curved root canals of posterior teeth,It is recommended to use no more than 6 times. High risk area the anterior or posterior straight root canal, a file that has been used 12 times,It is recommended to put it in this area to enter the next counting cycle. The counting knob is a three-color identification to indicate different risk zones. Each individual hole is attached with a counting ring.