50cm Plastic Classroom Square Ruler with Removable Handle. 228g. Introducing our 50cm Plastic Classroom Set Square Ruler, an essential tool tailored for educators who work with both whiteboards and blackboards. This versatile ruler features a removable handle for ease of use, allowing you to comfortably create precise angles and lines on various surfaces. With a 60-degree set square, it provides accuracy for geometric and mathematical illustrations. Crafted from durable plastic, this ruler is built to withstand frequent use in classroom environments. Whether you're teaching geometry, drafting diagrams, or illustrating concepts, our Classroom Set Square Ruler is the ideal companion for bringing clarity and precision to your lessons, whether on whiteboards or blackboards.