Yes you do need the hdmi mod to use these goggles. You see the telemetry but not the same screen as what is available through your main device unfortunately.@bobmyers thank you for the detailed info on the Sony goggles! I assume you are using them with the P3 HDMI add-on pack? I am a new user - does that HDMI pack allow you to see the flight telemetry (alt, speed, heading, batt life, etc.)? Or would you need a second person looking at the Go app's display?