Consists of a 6¼” diameter hard bronze circle with one fixed arm and two moveable arms. Each arm has an 18” ruler and a 13½” detachable extension ruler. The circular scale is graduated to half degrees with 10 degree markings.
Each arm is provided with a vernier reading to single minutes.
Four interchangeable pivot plugs are provided for determining and marking the location of the instrument center.
Available as left arm (WK-24-1175L) or right arm (WK-24-1175R).