Ebco P-DKL2K Door Knob Lock

Ebco P-DKL2K-AQ Door knob with push button locking is not just for looks. Once locked, there's no way to open it from the inside without using a key or the opening tool. The door knob comes with four different keys, and they're all dimpled so you can easily distinguish them from each other in the dark. The knob itself is 25mm across, and because of its deep mortise construction, it's suitable for a door up to 50mm thick.
A good door knob is more than just a place to turn your key—you also want one that's going to be secure against intruders and burglars. The best way to ensure this is by having a push-button locking system in your door knob.The push button automatically locks when it is pressed unless the key is used to unlock it first. This means that even though you can use this as an emergency egress, it still acts like a normal deadbolt if someone tries to force their way in.

A push-button door lock is used in the same way as a regular door knob, only instead of turning the knob to open or close the door, you press a button on the inside of the door to either latch or unlatch it. There's a separate key for this kind of knob that's used to unlatch it from the inside. It's a great way to keep kids from being able to get into your home if they accidentally lock themselves out, or if they're playing at home while you're gone and want to let someone in.