Metric Click Rule

This efficient, tactile, extension measuring tool is available in a metric version as well, making it a great tool for STEM subjects. The metric click rule measures items with accuracy to within one millimeter. The base unit, which measures up to 20 centimeters, consists of four major parts: 1/2-inch aluminum tube, sliding threaded rod, locking screw, and two 1/4-inch-thick metal stops. The sliding threaded rod, which measures up to 10 centimeters, is marked with raised lines in 1-centimeter intervals on the top and 1-millimeter intervals on the side. Each 1-millimetermovement of the rod also makes a clicking sound. The addition of multiple 20-centimeter extensions allows for the measurement of longer spans. Four 20-centimeter extensions are included, allowing for measurements up to 1 meter.