Companies face a variety of challenges in the product development of intelligent technical systems. On the one hand, companies have to manage a high level of product complexity and have to ensure efficient interdisciplinary cooperation. On the other hand, they must shorten the duration of the product development process and react quickly to changing requirements. Agile methods are a promising approach for these challenges. For example, agile methods shorten the duration of product development by eliminating a detailed initial planning. Furthermore, they enable a high degree of flexibility by using short iterations with quick feedback. Moreover, they ensure an optimally interdisciplinary collaboration by establishing development teams with experts from various specialized disciplines. Agile methods primarily focus on software development. However, intelligent technical systems consist of software components as well as hardware components. Therefore, the implementation of agile methods into the product development process is not trivial. For example, quick prototyping and active involvement of the customer within the development process is hard to realize for physical products. Therefore, the measuring of benefit potentials of agile methods and the tailored integration in the product development of intelligent technical systems is highly important. However, the mentioned challenges are barely addressed within current approaches. In order to adress these challenges, this paper presents an agile toolbox and a corresponding procedure model to integrate agile practices in the product development process of intelligent technical systems. First, the agile toolbox is developed by identifying individual practices of agile methods (e.g. iterative planning). Second, the presented procedure model enables the identification of company-specific requirements and the elaboration of a hybrid product development process based on the practices of the agile toolbox. The approach is validated by presenting an example from industrial practice.