What determines the lengths of files?

The length of a file is primarily determined by the distance between the point and the heel of the file. This length specification is crucial for determining the tool's effectiveness in various applications, as it influences the reach and control a user has over the filing action. Different tasks require different lengths of files; for example, shorter files are suitable for tight spaces, while longer files can cover more surface area quickly.

While the size of the teeth plays a role in the aggressiveness and type of cut, it does not affect the overall length of the file itself. Similarly, the shape of the handle is important for ergonomics and comfort but is also not a factor in determining length. The type of material being filed affects how the file is used and what file may be most appropriate, but it does not impact the physical length of the file. Therefore, the correct choice accurately reflects the standard definition of file lengths in tool specifications.