This 500mm core drill extension rod is designed for deep drilling in thick concrete. It connects between the drill rig and the core bit, featuring a 1 1/4" UNC male thread on one end and a 1 1/4" UNC female thread on the other. The high-quality steel construction ensures rigidity and prevents whipping, while the hollow shaft allows water to pass through for wet drilling applications. For even greater depths, multiple extensions can be connected together.