Yale R-YRD256-NR-619 Yale Assure Lock SL -Lose Your Keys. For Good. Introducing the slimmest electronic lock for your home; the Assure Lock SL. This sleek and modern touchscreen deadbolt allows homeowners to enjoy the convenience of 100% key free unlocking while enhancing curb appeal. Unlock your home without the hassle of keys by entering your 4-8 digit entry code on the keypad. Lock the door behind you by simply tapping the keypad. The lock is simple to install and even easier to use. Upgrade your Assure Lock SL with a Yale Smart Module to add it to your smart home or security system.