You gain three slots to put tinker specialties that you can hold for up to three weeks each or change after at least one. They are random, usually single-word things, like 'flames', 'robots', or even 'frogs'. While what you can build is vast in your specialties, they must fall within their topic: you wouldn't be able to create a cloning machine with 'robots', but could build an amphibian tank with 'frogs'. You can mix the specialties for better results, and things once built can be built again even after the specialty change, and can even be incorporated in new ones. You can maintain any tinker tech as well, regardless of your specialty. You don't have to change all specialties at once, but can’t hold the same one for longer than three weeks.