Niether, it's a button push lock. It disengages when the knob is twisted from the inside so it's easy to exit, but the knob doesn't work on the outside when the lock is engaged. On the outside, there's a small, 3 or 4mm hole that has a switch buried inside of it that disengages the lock so you can open it if you have a screwdriver or pencil or something of that nature.