A single-cylinder deadbolt is a type of lock commonly used on exterior doors. It features a keyhole on the outside and a thumb turn on the inside, allowing for easy locking and unlocking from within the home. This design provides a secure barrier against unauthorized entry while offering convenience for residents. These deadbolts are typically made of durable materials like steel or brass, enhancing their strength and resistance to tampering. They are often installed alongside a doorknob lock for added security. Proper installation and maintenance are essential to ensure optimal performance and safety.