This chapter addresses the supply networks of an input product, windows, to the construction industry. It provides a picture of the input side of construction solutions and how this relates to product innovation on an industry level. The chapter discusses the role of different domestic and international actors and their connectivity in the product innovation based on the example of the Polish windows manufacturing industry, taking the perspective of the domestic windows manufacturer. It shows that innovation is partly pushed by connected indirect actors forming the network of interactions. The chapter also addresses the connectivity dimension of innovation reflecting the existence of different types of interconnected interactions and different roles played by them in product innovation. It highlights which domestic and international actors are involved in the constant product innovation and what roles they play in this process.