Available for the first time in steel, the Reference 5905 self-winding flyback chronograph with Annual Calendar radiates a resolutely sporty look. The rhythmic dial features an elegant and casual "sunburst" olive green color. The integrated bracelet is enhanced by contrasting polished and satin finishes. Thanks to the vertical disk-type clutch, the central chronograph seconds hand can be used as a permanent (running) seconds display. The patented Annual Calendar automatically takes account of 30- and 31-day months, requiring only one correction per year, on March 1st.
Watch
Self-winding mechanical movement. 
Caliber : CH 28-520 QA 24H. 
Flyback Chronograph. 
Central chronograph hand. 
60-minute counter. 
Annual Calendar. 
Day, date, month and day/night indication displayed in apertures.
Dial : Olive green sunburst, gold applied hour markers.
Case : Steel. 
Diameter: 42 mm. 
Height: 14.13 mm. 
Water-resistant : 30 m. 
Sapphire crystal case back.
Bracelet : Steel. 
Fold-over clasp.
Diameter: 33 mm.
Thickness: 7.68 mm. 
Number of parts: 402. 
Jewels: 37. 
Power reserve: min. 45 hours - max. 55 hours. 
Winding rotor: 21K gold central rotor. 
Balance: Gyromax®. 
Frequency: 28,800 semi-oscillations/hour (4 Hz). 
Balance spring: Spiromax®. 
Hallmark: Patek Philippe Seal.