R8 Shank Ultra High Precision Keyless Drill Chuck, 1/8" - 5/8" Capacity, +/- .00078 Runout

The other reviews are spot on, this is the nicest quality chuck I've ever bought. The run-out is essentially non-existent on my Precision Matthews PM30 Mill. My ONLY complaint about it is that the chuck is only 1-3/16" deep (from the tip of the body, not to the tip of the jaws since that changes depending on the diameter of your bit). So you can't "choke up" on longer bits for more strength, you're stuck with however long your bit is (minus the 1.187" that will fit inside the chuck) sticking out. Keep in mind the 3 chuck jaws do extend away from the body of the chuck, which will grab onto more than the 1-3/16" that is sitting inside of the chuck, but the bigger the bit, the shorter the jaws extend before biting down. I just wish they would have bored into the butt of the tapered shank a bit to allow for more of the drill bit's "tail" to sit further up inside of there. I might just drill this out someday if I get enough courage to try to get through the hardened end of that shank. Otherwise, AMAZED at the quality and price!

This is by far the best drill chuck I've ever run. It's definitely worth it.

This chuck is the best drill chuck that I have purchased on Amazon so far

This is a nice chuck. Seems to be great quality and works perfect. I'd recommend it if you need one.