I actually stopped wearing my 6138-0017 "UFO" because I just didn't like the bracelet (and it was original!). It was flimsy, stretched out, and I just wasn't thrilled with it at all! While Seiko made some outstanding watches, I believe their bracelets were often sub-par. So, I decided to produce a bracelet custom-made for this classic chronograph. It is 18.7mm wide at the lugs, and fits models 6138-0010, 6138-0011 and 6138-0017. Not only that, but it is also the same size as the bracelet on the "Slide Rule" (6138-7000).
It is a heavy, solid-link bracelet with brushed metal, security clasp, and a truly awesome fit! It has removable links (with pins) and 3 holes on the buckle for micro-adjustment. Fits up to a large wrist. (Also compatible with the 7A28-7049 Sports Chronograph and 6139-8002 Speedtimer).