so many!
Solar panels #1 makes using added features easier,such as engle frig,sat t.v.
Side wall Insulation #2 But only when it is cold!
Sink with holding tank #3 (but then we stared out with bare shell)
Out side attached swing down table #4 (could be #2!)
Tinted windows #5 so i can see who is out side With out them seeing me!
One ,I can't figure the reason for was the 2 little wall mounted cabinet's that came with shell,taken out first day!.