Kidde 21008944 model KN-COB-B-LS battery operated carbon monoxide alarm provides you and your family with a loud warning signal against the dangers of elevated carbon monoxide levels in your home. Kidde 21007268 DC Basic alarm has a small, sleek design that is suitable for all living areas and includes multiple mounting options allowing installation on a wall or tabletop. Battery operated unit provides continuous protection for you and your family even during power outages.