Some watches tell the time; the Hamilton Khaki Aviation Converter Auto Chrono H76746540 also does the math. Its bi-directional rotating slide-rule bezel lets you calculate conversions and flight metrics at a glance, and in this version the tool sits around a sunburst blue dial paired with a brown leather strap for a warmer, more relaxed character.

Powering it is the H-21-Si automatic chronograph, a Hamilton movement with a silicon balance spring that improves resistance to magnetism and supports accuracy, along with a 60-hour power reserve. Functions include the chronograph, day, date and a tachymeter, all arranged neatly on the blue dial. The open caseback lets you see the chronograph mechanism in motion.

The 44mm stainless steel case has a screw-down crown and 100 meters of water resistance, so it’s more than a desk piece. The brown cow leather strap with H-Buckle softens the instrument look and makes this a great match for denim, a leather jacket or a weekend trip.

Blue Converter Auto Chrono H76746540 at a glance

• Collection: Khaki Aviation Converter Auto Chrono
• Case: 44mm stainless steel, screw-down crown
• Bezel: bi-directional slide rule
• Dial: sunburst blue; chronograph, day, date, tachymeter
• Movement: automatic H-21-Si with silicon balance spring
• Power reserve: 60 hours
• Crystal: sapphire, open caseback
• Water resistance: 100m / 10 bar
• Strap: brown cow leather, H-Buckle, 22mm lugs

A slide-rule chronograph with a blue dial that makes technical feel effortless.