Machinists, this one's for you! Here's a 2-pack of ER20 collet clamping nuts. These are essential for securing collets in your CNC milling machine, lathe chuck holder, or other tooling setups. They're the nuts that tighten down on your ER20 collets to grip tools securely. Unbranded but functional. US stock means faster shipping if you're in the States. New in original packaging. Perfect if you've lost a nut, need a spare, or are setting up new tooling. Make sure you have the right wrenches for installation. Simple but critical parts for anyone running ER20 tooling systems. Keep your machining precise!