This is a 20x20x20mm test cube specifically designed for calibrating 3D printing accuracy. It features a smooth surface and compact structure, with a clear “M” mark engraved on the top for easy identification and positioning. Its multi-layer nested design enables effective assessment of layer adhesion and dimensional stability during printing. It is ideal for printer bed leveling, nozzle height calibration, and material performance testing. Simple and practical, it is an essential tool for every 3D printing enthusiast.