Some tachymeter/telemeter/pulsometer watches featured spiral-type “snailed” scales on the dial. With the Chronoscope, Omega opted for a far more symmetrical look that features a couple concentric circles that come with the important scale details even though also not materially distracting from Main dial legibility. The advent of the 1st Submariner https://www.watchesworld.com/frozen-in-time-luxury-watches-for-winter/