The Ref. 5990/1A-011 Nautilus Travel Time chronograph is one of Patek Philippe’s rare steel watches. It features a new blue dial with a ray sunburst dial and a delicate black gradation to the periphery. The self-winding caliber CH 28-520 C FUS movement combines three convenient and user-friendly complications: a flyback chronograph, a Travel Time function (two time zones with two separate hour hands; the skeletonized hand shows home time) and an analog date at 12 o’clock which is synchronized with local time.

Watch
Self-winding mechanical movement. 
Caliber : CH 28-520 C FUS. 
Flyback chronograph. 
Central chronograph hand. 
60-minute counter. 
Two time zones: local and home time indication. 
Day/night indication for local time and home time in apertures. 
Date coupled with local time by hand.
Dial : Sunburst blue with black-gradient rim, horizontally embossed, gold applied hour markers with luminescent coating.
Case : Steel. 
Case diameter (10 - 4 o’clock): 40.5 mm. 
Height: 12.53 mm. 
Water resistant : 30 m. 
Screw-down crown. 
Sapphire crystal case back.
Bracelet : Steel. 
Patented fold-over clasp with lockable adjustment system.
Diameter: 31 mm. 
Thickness: 6.95 mm. 
Number of parts: 370. 
Jewels: 34. 
Power reserve: min. 45 hours - max. 55 hours.
Winding rotor: 21K gold central rotor. 
Balance: Gyromax®. 
Frequency: 28,800 semi-oscillations per hour (4 Hz). 
Balance spring: Spiromax®. 
Hallmark: Patek Philippe Seal.