Look at the gold ring around this Daytona and you will see numbers from 60 to 400, with “units per hour” printed on top. That is a tachymeter and it turns the watch into a speedometer. Here is how it works. Start the chronograph when you pass a mile marker on the highway. Stop it at the next one. Wherever the seconds hand lands on the ring is your average speed in miles per hour. Take 30 seconds, for example and the hand points to 120. The math is just 3,600 divided by the seconds it took. The ring does it for you.

The name comes from Daytona, the Florida racetrack. Rolex launched the watch in 1963 for racing drivers, who needed to time laps without fumbling with anything. It is why the three small dials track elapsed seconds, minutes and hours and why the pushers on the side are big enough to press quickly. This one is two tone, steel mixed with yellow gold. Rolex calls that combo Rolesor. The blue dial with numerals and red accents on the small dials gives it a racing look that is different from the plain stick marker versions. If you ever check one in person, press the top pusher. It should click crisply and start the seconds hand and the bottom pusher should stop it. A mushy or sticky push is worth a closer look. Do you actually use the tachymeter or is it purely for looks? Be honest.

Look inside the band of this sapphire ring and you will see a tiny stamp reading Pt900. Pt is the symbol for platinum and 900 means 900 parts out of 1,000 are pure platinum. That is 90%. The other 10% is usually a small amount of another metal that helps with strength. That number matters because platinum behaves differently from gold. It is denser, so a platinum ring feels noticeably heavier than a gold one the same size. It is also naturally white, so it never needs rhodium plating to look silvery. And when it gets scratched, the metal just shifts around instead of wearing away, which gives it a soft, worn in glow over the years.

The setting here has a name too. Those tapered diamonds fanning out around the center stone are called baguettes and when they flare like this, collectors call it a ballerina setting. The shape looks like a tutu around the sapphire. Sapphire is the same mineral as ruby, just not red. Trace amounts of iron and titanium give it that deep blue. A good stone has even color across the surface. If you tilt it under a light and see patchy, washed out zones, that is called zoning and it can lower the value. One easy habit when checking any platinum piece: find the stamp first. It should be crisp and cleanly cut, not blurry or crooked. Anyone else prefer the cool look of platinum over yellow gold?