The two barrels were developed for all Andreas Strehler movements and provide a guaranteed power reserve of 78 hours –  although the energy stored in both barrels would allow for a much longer period of time. They are connected in parallel and thus guarantee smooth winding and the even action of the two mainsprings.
Besides the generous power reserve, the use of two barrels brings further advantages, for example the almost total elimination of bearing pressure on the central wheel – thus avoiding stress on the pinions and gaining much higher precision.