Material and construction: Forged steel body provides good toughness and long-term wear resistance. High-frequency hardening plus black oxide finish increases surface hardness and offers improved corrosion resistance. Purpose and function: Designed as a clamping/nut wrench for collets and tool holders — used to tighten and loosen ER25 lathe clamping nuts, milling lathe nuts, and most compatible tool holders. Compatibility: Specifically fits ER25 collet nuts and is suitable for common milling and lathe tool-holder nut sizes that accept ER25-style clamping nuts. Ergonomics and control: Red rubber handle delivers a comfortable, slip-resistant grip, reduces hand fatigue, and ensures effective power transmission for reliable torque when tightening or loosening nuts. Accuracy and convenience: Solid construction and secure grip help maintain concentric clamping and repeatable clamping force, supporting consistent tool runout and setup accuracy. The tool makes nut changes faster and safer than using improvised tools. Durability and maintenance: Forged-steel core with heat treatment and black oxide surface minimizes wear and helps resist rust in normal shop conditions, reducing replacement frequency. Typical applications CNC lathe setups: Secure and release ER25 collet nuts during tool changes and routine setup to maintain concentricity and minimize runout. Milling machine work: Tighten milling head or tool-holder nuts on mills and machining centers that use ER25 collets for small-end tooling. Machine-shop maintenance and inspection: Fast, reliable nut removal and installation during tooling maintenance, inspection, or part changeovers. What you get A hardened, black-oxidized, forged-steel clamping nut wrench with a red rubber ergonomic handle, built for use with ER25 lathe/milling clamping nuts and most compatible tool holders.