Adjustable mounts allow trammel points to be fitted to variety of beams to create compasses of any length. Great for layout, marking, measuring and drawing any size circle or arc when normal compasses are not big enough. Easy to switch between lead and needle points. Includes fine-tipped needle points and 6 x #2 lead pieces for marking. Can be clamped to material 10 to 25mm (3/8 - 1") thick. Built-in storage for short leads.