The "smoke ash" nickname comes from its unique dial color that resembles the color of ash resulting from burnt wood or coal.
Specifications for the PAM 1662 Smoke Ash 
Case:
Diameter: 44mm
Thickness: 15.1mm
Water resistance: 300 meters
Bezel: Ceramic/Stainless steel with 60-minute scale
Crystal: Sapphire, scratch-resistant, anti-reflective coating
Movement:
Caliber: Panerai P.9010
Type: Automatic, in-house
Power reserve: 48 hours
Functions: Hours, minutes, small seconds, date
Dial:
Color: Smoke ash
Hands: Luminescent, skeletonized, baton-shaped
Hour markers: Luminescent, Arabic numerals and indexes
Date display: At 3 o'clock position
Strap:
Material: Brown leather
Limited edition:
Production: Limited to 150 pieces
Special feature: Engraved with the limited edition number on the caseback