The Jacobs Super 18N 4JT 1/8-3/4" 3-9 MM Cap Ball Bearing Drill Chuck 4MT is a high-quality drill chuck designed for precision machining and metalworking applications. Made in the United States by Jacobs Super, a trusted brand in the industry, this chuck features a ball-bearing design for smooth and reliable operation. With a 4JT mounting size, this drill chuck is compatible with a range of drill sizes from 1/8" to 3/4" (3-9 MM) and is perfect for stable and accurate toolholding in CNC machines and other industrial applications.