Possible Clues:

• Openings
• Rock band that you might think would always be an opening act, with 'the'?
• 'Light My Fire' band, with 'the'
• Sliding or revolving items
• American rock band missing the openings
• Some are revolving
• Upsets cross section initially providing access to both Houses
• Some slide and some revolve
• They might swing or revolve
• Ways in and out