Primary SAFE-T Ruler is exactly 12” long with no lead-in space. This feature enables children to measure starting at the “end”. The scales are simple and easy to read beginning with 1" markings on one edge, 1/2” markings on the second edge, 1/4” markings on the third edge and 1 cm markings on the fourth edge providing 4 rulers in one. Flexibility allows the introduction of measuring arcs and circles. This ruler was designed by teachers as the ultimate tool for teaching linear measurement.