Electrical door strike having a locking mechanism operating under pressure, comprising: a door strike house , a movable strike keeper which rotates in a movement space about an axis substantially parallel to the longitudinal direction of the door strike, a strike keeper locking mechanism, comprising: a barrel in the door strike house with a central axis and with an opening adjacent the movement space of the strike keeper; a first movable member , shaped like a ball with radius r, located inside the barrel near the said opening ; a second rotatable member positioned so as to cut off the central axis of the barrel, with a rotational axis substantially orthogonal to and crossing the central axis of the barrel at a point a at a distance l from the said opening of the barrel, and extending a distance in a radial direction from its axis of rotation which varies gradually with its angle of rotation θ , so that the total extent x of the two members, from point α , along the central axis of the barrel, when resting against each other, is smaller or equal to l at an angle of rotation θ2 (open strike keeper) and greater than l at another rotation angle θ1 (locked strike keeper), and a rotation mechanism for rotating the second member, characterized in that the central axis of the barrel is substantially parallel to the axis of rotation of the strike keeper. a door strike house , a movable strike keeper which rotates in a movement space about an axis substantially parallel to the longitudinal direction of the door strike, a strike keeper locking mechanism, comprising: a barrel in the door strike house with a central axis and with an opening adjacent the movement space of the strike keeper; a first movable member , shaped like a ball with radius r, located inside the barrel near the said opening ; a second rotatable member positioned so as to cut off the central axis of the barrel, with a rotational axis substantially orthogonal to and crossing the central axis of the barrel at a point a at a distance l from the said opening of the barrel, and extending a distance in a radial direction from its axis of rotation which varies gradually with its angle of rotation θ , so that the total extent x of the two members, from point α , along the central axis of the barrel, when resting against each other, is smaller or equal to l at an angle of rotation θ2 (open strike keeper) and greater than l at another rotation angle θ1 (locked strike keeper), and a rotation mechanism for rotating the second member, characterized in that the central axis of the barrel is substantially parallel to the axis of rotation of the strike keeper. a barrel in the door strike house with a central axis and with an opening adjacent the movement space of the strike keeper; a first movable member , shaped like a ball with radius r, located inside the barrel near the said opening ; a second rotatable member positioned so as to cut off the central axis of the barrel, with a rotational axis substantially orthogonal to and crossing the central axis of the barrel at a point a at a distance l from the said opening of the barrel, and extending a distance in a radial direction from its axis of rotation which varies gradually with its angle of rotation θ , so that the total extent x of the two members, from point α , along the central axis of the barrel, when resting against each other, is smaller or equal to l at an angle of rotation θ2 (open strike keeper) and greater than l at another rotation angle θ1 (locked strike keeper), and a rotation mechanism for rotating the second member, characterized in that the central axis of the barrel is substantially parallel to the axis of rotation of the strike keeper. <EOS>