Help please

[murraymints]

What's the difference between apple t.v 2nd gen and the 3rd gen I really don't get it. I've sold one on eBay thinking it was a 2nd gen n been told its not. It's the 3rd one I've got

 

[Redneck_Randy]

ATV2 is 720p and the ATV3 is 1080p