Every character occupies the exact same horizontal width. In a proportional font, an 'i' is narrow and a 'W' is wide. In DS ISO 1, an 'i' has massive side-bearings, and a 'W' is squished slightly. This is crucial for aligning dimensions in columns or tables on a drawing.

: Used to display standardized symbols and text in CAD software. Standardized Exchange

First, let’s decode the name.

This is the most famous feature. To distinguish zero from the capital O, DS ISO 1 automatically renders 0 with a forward slash. Some variants use a dotted zero, but the ISO standard prefers the slash.