As the industry leader, Kwikset has provided trusted security for over 60 years and has become synonymous with security, peace of mind, style and innovation. The largest-selling deadbolt in America, the 600 series provides tough, effective protection at an . This single cylinder deadbolt can be locked or unlocked by a key on the outside, or the turn button on the inside. SmartKey Re-key Technology allows you to control who has access to your home. Re-key the lock yourself in seconds in 3 easy steps. Have you recently moved or had a child lose a key? It's time to re-key. SmartKey provides the highest level of residential security and features BumpGuard to protect against lock bumping. The crisp, clean appearance of the Satin Nickel finish adds to the overall look of the product and brings a modern feel.