The governing principle of marking out is that a clear reference line is made by a tool harder than the work, drawn to a fine point so the line is thin and exact.

A scriber is used to lay out lines on a metal workpiece before it is cut, filed, or drilled.

Its tip is made of hardened steel ground to a sharp point, so it stays harder than most workpieces and keeps its edge instead of blunting.

The hard, pointed tip presses into the surface and cuts a thin, bright scratch line that remains visible even under workshop light and oil, which is exactly what accurate marking needs.

A graduated measuring scale would let you read a distance but cannot itself scratch a line, so that is not the working feature.

A flexible rubber grip only aids holding comfort and has nothing to do with cutting the mark.

A wide flat blade would smear a broad, imprecise mark rather than a fine line, so it fails the accuracy the job requires.

Hence, the answer is Hard pointed tip.