7th Avenue line up
Three of the huge open top double deckers that Gray Line operate in Manhattan on sightseeing tours. There are clearly at least two different models in use. I seem to recall the word Enviro on one - but like many new buses in New York not much info on make or model that I could see.
The top deck roofs get removed as the day warms up - as can be seen on the rightmost example - which is a Dennis Trident