For over 70 years, Kwikset has been the industry leader in home security, offering trusted protection and peace of mind. The 600 series is America’s best-selling deadbolt, delivering strong security at an affordable price. This single-cylinder deadbolt operates with a key from the outside and a thumb turn on the inside, combining convenience with reliable safety. | Kwikset | | SmartKey Security Polished Brass Metal Single Cylinder Deadbolt | Best Buy