Hold the older model. The strips are for no-go regions. It's got a fall sensor for stairs, mine hasn't fallen down the stairs. I certainly won't simply call it a garbage vac as mine is really pretty good (Here is the model with Alexa which was on sale at Amazon http://vaccumrepairnearmeboulder31739.ezblogz.com/24870821/the-basic-principles-of-service-dyson-vacuum-cleaner-boulder