This submarine is the first in the world to be equipped with an ultra-modern hydrogen fuel cell engine and can operate submerged for weeks independently of external air without needing to come to the surface. The armament includes the newly developed heavy-weight Seehecht torpedo that is launched from six torpedo tubes. The submarine can be built as a dived or a surfaced version, detailed hull with recessed panel lines, transparent part for the fin area, propeller, 4 separate rudders aft, 2 movable diving planes on fin, rear stabilizers, equipment on top of fin optionally up (periscope, antenna mast, exhaust mast etc), separate front hatch/side door, bitt and mast on gangway and display stand. Decals with draught markings for the following versions: German Navy test periode U31/U32/U33/U34; German Navy Commissionning U31/U32/U33/U34 and Italian Navy.