These Seiko 6139 chronographs with black pulsations dials are becoming hard to find these days. This example in stainless steel measures 40mm and remains very clean and unpolished considering it dates to circa 1969. The original black dial is the hard-to-find pulsations version. The original recessed Seiko crown is still present. The Seiko chronograph automatic winding movement was just cleaned and is accurate with all functions operating smoothly. These look very cool and sleek on the wrist.