Steel rulers are strong and hefty to maintain straightness and prevent distortion of the scale. They are best suited for dry environments where they won't rust. These rulers make length measurements and also work as straight edges to draw and check straight lines.

Stainless steel rulers withstand exposure to water, humidity, and other harsh conditions that could cause steel rulers to rust and wood rulers to decay. They are more corrosion resistant, stronger, and heftier than aluminum to maintain straightness and prevent distortion of the scale. These rulers make length measurements and also work as straight edges to draw and check straight lines.

Aluminum rulers are more corrosion resistant than steel and generally lighter but less rigid than other metal rulers. They make length measurements and also work as straight edges to draw and check straight lines.