Stairway Gates are specially designed to open in one direction - away from the stairs. This feature makes your stairway much safer to use when the gate is installed. As an example; if you were to be coming up the stairs, opening the gate towards you would require you to back up to allow for the swinging motion of the gate door.
Stairway gates come with an adapter to let you control the direction in which the gate will open. You may install these gates without this adapter piece if you were to use the gate in another situation, but when over stairs it becomes a very important safety feature.