The Nudos shavers with NiCd cells can be recharged in 30 minutes by means of a Fly Back Self Oscillating Power Supply (SOPS). This electronic circuit enables cells to be recharged at 100-240 V . It is possible to shave directly from the mains, provided the voltage exceeds 100V . The on/off slide has a locking device, which prevents the shaver from being switched on accidentally. Leaving it connected to the mains after it is fully charged will not damage the shaver. However, the life of the cells may be shortened if the shaver is kept permanently connected. If the shaver is kept in the case when charging, make sure that the lid is open to prevent overheating.