Abstract: An opener for opening flaky fiber material comprising a driven opening disk having a first side and a second side and which rotates in a direction; a first plurality of spikes is mounted on the first side of the opening disk; a counter opening disk which has a circumference, a first side facing the opening disc and a second side, fixedly mounted parallel and opposite to the first side of the opening disk; a second plurality of spikes is mounted on the first side of the counter opening disk and is fitted so as to tilt at an angle in a direction of the opening disk and is arranged substantially radially in rows, and a drive mechanism for moving the angle of at least one row of the spikes on the counter opening disk back and forth in the rotational direction and counter to the rotational direction of the opening disk.