The PB02301A1B1A1 reference is the Navitimer B02 Chronograph 41 Cosmonaute, and this Breitling Navitimer Cosmonaute replica pairs a steel case and bracelet with a black 24-hour dial for maximum contrast and legibility. At 41mm, it falls into the mid-size Navitimer range that balances the detailed circular slide rule bezel against a case diameter comfortable on most wrist sizes. The 24-hour dial completely transforms what is traditionally positioned as an aviation tool into a space-flight instrument: Scott Carpenter wore a Navitimer with this layout on the Aurora 7 mission in 1962 so he could tell day from night in orbit.

That flight is one chapter in a longer story, and our guide covers the wider Navitimer aviation history. Day to day, remember that the B02 has no rotor: the watch stops if it sits in a drawer for a couple of days, so wind it by the crown each morning until you feel resistance.

Specifications

• Model: Navitimer B02 Chronograph 41 Cosmonaute (genuine limited to 362 pieces)
• Reference: PB02301A1B1A1
• Case size: 41 mm
• Case: stainless steel (genuine: steel with a 950 platinum bezel)
• Dial: black 24-hour dial with cream Arabic numerals, three black counters, date in the 6 o’clock counter
• Bezel: bidirectional slide rule, polished steel (genuine: platinum)
• Crystal: sapphire with anti-reflective coating
• Bracelet: stainless steel seven-row with folding clasp
• Movement: clone Cal. B02, hand-wound chronograph, 28,800 vph
• Functions: hours on a 24-hour scale, minutes, small seconds, chronograph, date
• Power reserve: 55 hours (genuine Cal. B02: 70 hours)
• Water resistance: 30 m (same as genuine)

How to Read the Cosmonaute 24-Hour Dial

The short hand makes one turn a day instead of two: it points to 24 at midnight and straight down at noon, so one glance tells day from night. This keeps the time clear across long flights and time-zone changes, without the guesswork a 12-hour dial can leave at three in the morning.

Steel Case, Cream Numerals, Black Counters

The steel construction keeps the weight close to other steel Navitimer references at the same 41mm diameter. Wrist presence comes from the dial instead: large cream numerals that no other Navitimer in this collection carries. The black dial provides high contrast against the cream numerals and the lume on the hands, improving legibility, while the three counters stay black on black for a calmer look. Breitling polishes the case sides while brushing the lugs, creating visual depth through mixed surface textures. For a different size and color approach in the same collection, consider the 35mm blue alligator A17395161C. More Navitimer references are available in the Navitimer collection.

Clone Cal. B02: Hand-Wound, 55 Hours

The genuine Cal. B02 is the hand-wound sibling of the B01, built without a rotor. This clone Cal. B02 follows the same idea: no self-winding, a crown you turn by hand, and about 55 hours of running time from a full wind, against 70 hours for the genuine calibre. The chronograph works as on the B01, with the counters at 3 and 6 totalling minutes and hours and the small seconds at 9.

Living With a Steel Cosmonaute Every Day

Wearing a Cosmonaute shifts the entire context of the watch on wrist. The slide rule bezel becomes less about flight calculations and more about visual texture, with each numeral catching ambient light along the polished steel. The steel bracelet drapes with a weight that leather or rubber straps cannot approximate. The genuine PB02301 was limited to 362 pieces, so this hand-wound B02 replica is the practical way to wear the same 24-hour dial without hunting for one of them.