1PC Professional Compass Geometry Set with Lock Math and Precision Compass Metal and Durable for Solid and Plane Precis PRECISION MATH COMPASS - Made for mathematical geometry and art drawing. Unique design to prevent slip while drawing. _x000D_ _x000D_ PRECISE ADJUSTMENT - The adjustment knob enables students to produce accurate geometric constructions. You can lock the compass in place and have it actually stay when writing. _x000D_ _x000D_ ADJUSTABLE SIZE - Maximum diameter up to 10 inches, minimum for 1/8 inch. You can draw all kinds of circles. _x000D_ _x000D_ ALL-METAL MATERIAL - Made from high quality parts and solid construction, durable enough to last for a long time. Three additional leads are easy to replace when needed. _x000D_ _x000D_ Stability: The compass with spring bow head and thumbwheel could prevent from unintended slide. _x000D_ _x000D_ colour: blue/black _x000D_ _x000D_ Materials: Metal _x000D_ _x000D_ Package Contents: _x000D_ _x000D_ 1 * Precision Compass _x000D_ _x000D_ 2 * Spare Screws _x000D_ _x000D_ 3 * Spare Lead _x000D_ _x000D_ Only the above package content, other products are not included. _x000D_ _x000D_ _x000D_ Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_ _x000D_