This paper presents a study on the potential of today's smartwatches as a complementary user interface to mobile support systems for industrial maintenance tasks. Starting from challenges, usage scenarios and use cases for the valuable use of smartwatches in an industrial context, the various possibilities of information delivery, task support and process control using smartwatches are evaluated and checked against basic ergonomic requirements on data pre-processing, user interface design and the hardware equipment. A prototypical implementation of a support system for industrial maintenance tasks illustrates the applicability of the derived interaction concepts and design guidelines for smartwatch-equipped mobile support systems.