The Schlage Bell Satin Chrome Entry Door Knob is perfect for use on exterior doors where extra security is needed. The Bell Knob is a practical door knob with clean lines, and the subtle luster of the Satin Chrome is edgy and alluring. The knob unlocks when the door is opened from the inside, allowing you to leave quickly and conveniently and re-enter easily. Plus, it was designed and tested with strength and durability in mind.