Movement Mechanical hand winding, personalized to U-boat specifications for stem to be positioned at 9 o`clock, diameter 36,60 mm. Shock absorber Incabloc, blued screws, visible rubies. Frequency 18.000 vibrations per hour, 2,5 Hz. Power reserve 46 hours. 17 jewels, height 4,5 mm. Functions Hours, minutes, small seconds at 3. Case Steel 316L AISI, satin finish, PVD coating treatment, sand blast finish. There are 8 steel screws which lock up the back case from the upper side. Serial number engraved on the right hand side of the case. Crown at 9. Diameter 50 mm. Thickness 15,00 mm. Weight 140 g approx. Back See-through, with exclusive steel grate. Dial Black with brown hands and index or brown dial with black hands and index. Crystal Sapphire, scratchproof, 1,40 mm thick. Strap Black in rubber hypoallergenic with calf inset. Width 26/20 mm. Tongue buckle with U-Boat personalization. Available also with strap in rubber with brown python inset (ref 5418). Water-resistance 100 metres, 10 ATM.