new unit

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Bill,

If seeking a 12" display with internal CHIRP (conical) sonar / DownVision sonar, then an a128 MFD or eS128 MFD would be recommended. Many prefer the option of having buttons as well as touchscreen and opt accordingly for the e128 or will accessorize the a128 MFD with a RMK-9 Remote Keypad. Should the MFD be installed in a location affording it an unobstructed view of the skies overhead, then an external GPS antenna or external GPS Sensor should not typically be required. Bimini tops rarely pose issues with GPS reception for these MFDs.