This drafting compass is most commonly used to measure inside or outside diameters and reproduce circles and arcs. Often used with maps or architecture, the wing divider features a pencil holder to easily plot curves and lines. With a lockable wing for repeat measurements, this locking wing divider is a great tool for architects, carpenters, cartographers and mathematicians! Lockable (y/n): Yes Material: HCS Leg length (in.): 6 in.