A sliding element works with a guide system having two guide parts that can be moved relative to one another. The sliding element can be fixed to one of the guide parts by an attachment face (3) and includes, on a face opposite the attachment face (3), a sliding surface (6) so as to be slidingly supported on the other guide part. The sliding element includes a first part (I) and a second part (2) which is mounted so as to be rotatable relative thereto, which parts include a contact surface (3) for mutual support. The contact surface (7) is axially inclined in a rotational direction of the second part (2) counter to the first part (I), and the two parts (I, 2) can be locked to one another in various angular positions and the locking can be released.