Hydro-dipping (also known as water transfer printing, cubic printing, immersion printing, and hydrographics) is the process of applying a graphic design to a three-dimensional object via water immersion. In other words, you dip stuff into ink-covered water and end up with ink-covered stuff.
The process allows for the decoration of a wide variety of objects, as the only general stipulation is that the objects themselves be waterproof. (Computer cases and baby bottles are dippable; computer processors and babies are not dippable.) Commonly hydro-dipped items include auto parts (rims, dashboards, interior trim), gun parts (grips, stock, barrels), and electronics accessories (mobile phone cases, stereo faceplaces, video game controllers).