What is the difference between a dSF11, dSF12 and dSF20? digitalSTROM Support September 28, 2018 06:02 Updated Follow The filter has been constantly optimized (better filter performance, function display etc.). The dSF20 should be used for new installations. Related articles How much power is required to protect a dSF filter? Can I control digitalSTROM by voice commands? What is the difference between a dSM11 and a dSM12? How can fluorescent lamps (FL) be used?