Application The accuracy collet chuck holder for professionals and hobbyists demanding milling and drilling applications, simple to use and easy to operate. Specification ER40 clamping range: 2-26mm Spindle Drawbar thread: 5/8"-11 Accuracy: 0.0005inch Collet Sizes: 1/8, 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, 1 inch Excellent stability ER-40 Chuck Shank has stable performance and Spring Collet Chuck Tool Holder is highly accurate and stable. Accuracy crafted Accuracy ground inside and out, made of high quality alloy steel for strength and durability. Higher overall toughness and longer service life. Packing Included 1 x #40 ER40 Collet Chuck, 1 x Wrench/Spanner, 8 x ER40 Collet Set.