Marten-Free-Flex | marten deterrent for electric cars & combustion engines GARDIGO Marten-Free-Flex is a marten deterrent that we have developed for use in electric cars, but which can also be used in combustion engines or even in the attic. This is made possible by the flexible power supply. The device can be connected to the 12 V car battery using the cable supplied. Electric cars also have these, namely for the on-board electronics. If the car manufacturer prohibits the connection of devices to the battery - or if this is too cumbersome - the marten repeller can also simply be operated with standard AA batteries.