Starrett 36 Series Outside Calipers feature lock-joint transfer type calipers with fine-adjustment. One of the handiest and most versatile calipers ever made, Starrett Lock-Joint Transfer Calipers feature a transfer arm, a fine-adjustment screw, and a locing joint. Legs are made from a high-grade steel, rugged in construction, and well-finished.Caliper size and capacity is 12". 12”/300mm (Outside).