Triangular File for Working at Height Find the finest triangular file for working at height with the Secure Tools selection. We have triangular files of all sizes for every different job. Each file has been specifically customised with an anti-drop handle for secure tethering and safer and more secure working at all heights. A triangular file is primarily used for trimming and sharpening edges and surfaces. Its three-sided shape makes it ideal for sharpening difficult-to-reach areas like saw teeth, and this style of file will last for many years if properly cared for and cleaned.Secure Tools is a trusted provider, and we have a first-rate range of triangular files for working at height.