When we say 4/3mm or 3/2mm or 2/2mm, this corresponds to the neoprene thickness distribution on the wetsuit. The distribution of neoprene is meticulously chosen to optimize warmth and flexibility and thus enhance your performance on the wave. The lower thickness is on the upper body: shoulder + arms, as well as on the lower legs to maximize freedom of movement. The top layer is on the rest of the body to maximize warmth. The 4/3mm wetsuit is ideal for water temperatures between 10°C and 14°C. The 3/2mm wetsuit is ideal between 14°C and 18°C. The 2/2mm wetsuit is ideal for water temperaturesabove 18°C. Of course, outdoor conditions can increase the feeling of cold.