Bringing electrochemical reactions to technical scale is a difficult task and important challenge towards a chemical industry powered by renewable electricity. Chemists and Chemical Engineers need to work hand in hand to bridge from lab scale glassware to technical electrolyzer. Stitt et al. illustrated this importance for non-electrochemical multiphase reactions [Chem. Eng J. 90 (2002) 47-60, Fig. 3]. Inspired by this we prepared a new illustration pointing to the importance for proper upscaling of electrochemical reactions. Eva Kolle-Görgen draw the draft and final illustration. Bastian J. M. Etzold had the idea and contributed with suggestions.