This high quality 6in bow compass is made of rolled brass with a durable nickel-plated satin finish. It features a smooth-action, rapid adjustment feature with a sturdy push-button mechanism and center wheel for fine adjustments. Its double knee-joints allow for parallel leg positioning and use with an extension beam, ruling pen or universal adapter. It can be used to draw circles up to 14in in diameter and up to 23in in diameter with use of the included extension beam. The set also contains a universal pen adapter and two spare leads, packaged in a reusable plastic case.