This particular model, crafted by the Daini division, presents a sleeker and slimmer profile compared to the 6139 series produced by Suwa. It was developed as a response to Suwa's line. Along with its more compact size, it boasts a distinctive "flyback" function, allowing the chronograph sweep to be reset without the need to first stop the mechanism.
 
The example we have from December 1971 is in pristine condition, as if it were manufactured to today's standards. The dial is a striking matte black, accentuated by an orange minute track and the "Speed Timer" designation. It features a rotating inner bezel adorned with silver and steel gray markers.
 
The hour and minute hands are polished beveled batons that harmonize with the applied markers, while the vibrant orange sweep hand adds an attractive touch. Being a JDM variant, the day display can be switched between English and Kanji characters and is positioned alongside the date under a polished frame. The tonneau case exhibits refined contours, and its flared sides contribute to making this model one of the most comfortable designs in the Speedtimer series, suitable for daily wear.