Keyed Entry (Single Cylinder) Function: Single cylinder keyed entry door hardware is locked and unlocked from the exterior using a key and can be locked and unlocked from the interior using the locking mechanism. Perfect for securing entrances, side doors, and anywhere else that needs a bit more security. Product Technology: Solid metal Construction: This product begins with raw bars of solid metal which are heated, and pounded into specially made dies -producing a stronger, more substantial product. The difference between lesser metals and heat forged metal is noticeable the minute you hold it in your hands -?solid metal is heavier, smoother, and naturally resists corrosion.