FPV-Power 12V Regulators are designed to be used with sounder units that require a minimum of 11V to run, providing a constant 12V to the fish finder right until the battery reaches its safety cutoff.
FPV-Power 12v Regulator 5a
The regulator is installed inline between the battery and sounder and prevents the unit from cutting out when the battery capacity drops to 1/4 to 1/3 capacity. Also commonly used to prevent your sounder from shutting down if you are running other high draw items (such as a Power-Pole Micro) from the same battery