Banknotes are a high-tech product manufactured in sophisticated technical processes. Nowadays central banks expect banknotes to have a performant life-time. The manufacturer accordingly designs the product to meet that expectation. For production, but also for independent quality control, a well-defined specification is indispensable. All technical parameters need to be defined with target values and tolerances as well as underlying standard test methods and related conditions. In this chatbox, the requirements of technical product specifications for banknotes and banknote substrates will be discussed.