Perfect for use by students or professionals, this set contains two drafting essentials. The 6in Pro Bow Compass is made of rolled brass with a durable nickel-plated satin finish. It features an accurate center wheel adjustment with a built-in spindle stop to prevent over-extension. The compass can be used to draw circles up to 16in in diameter. Its double knee-joints allow for parallel leg positioning and use with an extension beam, universal adapter or the included ruling pen. The ruling pen can also be used separately to create precise lines and drawings with ink, drawing and masking fluids or even thin paints. The set additionally includes two replacement leads and is packaged in a reusable plastic case.