CVSTOS Challenge SEA-LINER GMT blue steel 5n red gold New/old stock discontinued Cvstos check up revision Delivered with 2 years warranty ! Medium case : 41×53.7mm Delivered with Blue rubber strap with new generation double folding clasp Optional straps: Alligator , Alcantara Technical description : Tonneau-shaped, 53.70mm x 41mm CHALLENGE case Back Open with sapphire crystal. Sapphire, non-reflective coating 2 sides. Crystal 100 meters Water resistance Screws Polished titanium grade 5 or 5N red gold. Exclusive CVSTOS TECHNOLOGY pattern. Screwed, polished titanium grade 5 or 5N red gold, Crown Nitrile insert. Dial Base made of teck wood. Polished and satin-finished