This external flow metal handle insert is made with a slimmer tip for better perio scaling of the calculus on the sensitive areas of the mouth. It gives the dental hygienist the ability to reach hard to clean areas of the mouth. Bonart's slim inserts provide the same functionality as most major brands. Available in both 25khz and 30khz. This insert is made with American made stainless steel tips, and nickel strip stack. External water flow and metal handle.