Sleep Number is the name of airbeds made and sold by Select Comfort. All Select Comfort air beds bear the brand name Sleep Number. The name comes from the number of the firmness setting on the Select Comfort airbed remote control, made famous by the question in advertisements, "What is your Sleep Number?"
Select Comfort/Sleep Number does sell adjustable beds as bases for their airbeds under the brand name Flex Fit. There are three models: FlexFit 1, FlexFit 2, and Flex Fit 3. They also sell a modular foundation and a steel bed frame.