The largest-selling deadbolt in America, the 600 series provide tough, effective protection at an affordable price. This single cylinder deadbolt is operated by a key on the outside, or a thumb turn on the inside. Secure your front door with Kwikset keyed entry door locks, security sets and deadbolts. Recommended for exterior-facing doors or securing interior rooms with a key for maximum privacy. Choose from a variety of stylish finishes to match your home décor. Kwikset is the 1 selling U.S. lock brand, protecting families with trusted security since 1946. Kwikset offers smart, simple, stylish and secure door hardware for every home or business need — from mechanical locks with patented SmartKey Security to innovative and flexible smart home technology. YipitData Unit Share Report, 2026.