Sturdy steel construction delivers durable, long lasting performance for CNC toolholding tasks. strength and hardness provide reliable and secure nut locking and removal for ER type toolholder cutter bars and extension bars. Wide compatibility with ER16, ER20, ER25, ER32, and ER40 models, suitable for a range of collet chuck machine tools. Available in red or black, offering a practical color option for your workshop. Use scenario: In a CNC milling setup, use to lock or loosen ER collet tool holders during tool changes to maintain precision and keep downtime minimal. Use scenario: On a multiaxis machining center, employ to secure cutter bars and extension bars during setup or maintenance for stable operation. Use scenario: During routine maintenance, use to remove stubborn or overtightened nuts on ER style tool holders, improving service efficiency.