CF letters in a hexagon symbol are used on dimensions or tolerances in technical drawings to specify “Continuous Feature” in the technical drawings as shown in the figure.
Continuous Feature symbol: 
- Continuous Feature is divided or separated by features on the material.
- Continuous Features have the same geometrical and dimensional properties.
Note: If there is a continuous feature in the technical document, My advice is to make a continuous feature in one operation in the manufacturing process if it is possible.
