Laser cut cardboard stencil for the 10L trinkwasser can. This type of stencil produces a superior look to the normal vinyl sticker type stencils. This will give you that soft edge over spray that you see on virtually every original. The hard edges made by vinyl stencils has always bugged me a little. Plus, you only need the one to paint all four sides of your can.
There is a little charring around the cut edges, but I have not noticed this affecting the paint job and the laser cut cardboard provides a slightly better and cleaner stencil than the 3D printed ones I offered previously. The cardboard stencils are effectively the same and produce the same quality finish, but I foolishly sold my sample 10L trinkwasser so I do not have it here to do a comparison photo.