Guaranteed Water Resistance to 1000m

The "U1" series from German watch brand SINN is a dive watch model that boasts impressive specifications, including a 1000m water resistance rating, and features time, minute, second, and date displays.

The new "U1.S" and "U1.S.E" models feature a black hard coating applied to steel from Germany's latest state-of-the-art submarine, the U-boat.

This black hard coating is achieved by applying a black PVD coating over SINN's proprietary Tegiment technology (surface hardening), which not only changes the color but also provides exceptional scratch resistance.

Tegiment is a technology that hardens the steel's surface by diffusing and permeating carbon molecules through carburization using nitrogen, followed by quenching. This process achieves a surface hardness equal to or greater than ceramic, preventing scratches on the watch.

This treatment can be applied regardless of the case's finish, whether matte or polished. Furthermore, it prevents nickel from migrating to the surface, making it safe for individuals with nickel allergies.