text: Pneumatic Vacuum Elevators operate without cables or pistons and can be installed more easily and quickly than their alternatives since their housing is composed of prefabricated sections which are considerably narrower than conventional lift shafts .
simplified: Pneumatic or `` Vacuum '' elevators operate without cables and can be installed more easily and quickly than their alternatives since their housing comprises prefabricated sections which are considerably narrower than conventional lift shafts .