The digital technology of the beltpack offered new opportunities for the user interface. Inspired by contemporary iPods, the volume controls don’t need physical knobs (encoders) but can be engineered with capacitive sensors instead. For a beltpack which is often used in poorly illuminated, difficult conditions, ease of use is even more critical. The two cavities in the front can be handled blindly. The overall design can therefore be carried out in an extremely smooth manner, while following the design philosophy of the desktop products with maximized simplicity and readability on the foreground (see also Pro Line & Flexus).