Most likely 24V. If you have Humminbird fishfinders, get a Minn Kota Ultrex or Quest Ultrex; if you have Garmin fishfinders, get a Garmin Force; if you have Lowrance fishfinders, get a Lowrance Ghost. If you think that you will never need a foot control, the Terrova or Ulterra work, although I got to a point where I needed foot control (or at least better than what my Terrova offered), which is why I switched from a Terrova to an Ultrex.