and automatic and helium escape valve

with a sapphire crystal featuring anti-reflective treatment and a transparent sapphire caseback revealing the precision mechanics inside

elegant look

adding an ethereal quality to this timeless watch

U-Boat Watch Darkmoon 44 Aquamarine Curve Black PVD Temple Colour_Grey and automatic and helium escapeU Boat Swiss Made Ronda 712 Quartz Movement Lubricated with an Oil Bath Working between 0 +60C when not worn. 44mm AISI Black PVD 316L Stainless Steel Case Completely Filled with a Special Oil that Emphasises and Improves Legibility on the Dial High Quality Domed Sapphire Crystal Glass with Anti Reflection Treatment Innovative Locking System with Quick Battery Replacement Distinguishing Crown on Left Side Screwed In Black PVD 316L Stainless Steel Case