Sega Mega Drive 2 (US: Sega Genesis 2)
The Mega Drive 2 was an update to the original Mega Drive, I bought these as a big box job lot from a car boot sale, there was four consoles but no power pack. It uses a different power supply to the Mega Drive, so at the moment, these are still untested.
The new version drops the RF out, headphone socket and volume control, and now has stereo sound from the A/V out socket
The edge connector is the same as before, although the Mega CD was updated to match the new aesthetics
As there was no RF out on the updated console, there was a RF adaptor instead, which had a pass through for the TV aerial
I have this as well, it has more pins in the plug, no idea if it's for this console or not.
Update
I picked up another one of these recently, it's slightly different to the one above, but has the same model number
For more retro hardware check out my online museum here