We are an architectural and landscape architectural office. Several of my staff use these parallel gliders in two different sizes. The 14" is the most popular since it measure 12 inches.

The Alvin Pro Parallel Glider is a solid piece of drafting equipment. Must have for professionals. They're not invincible, but when taken care of, they can last for years and years. And DEW Drafting Supplies is an awesome company with good prices and exceptional customer service!

Had several "rolling rulers" & broke lessers versions. I had the smaller version of this one for a couple years and had to get the larger one because of the durability, practicality and design. Its an excellent addition to any desk.