A releasable fastening device, comprising a socket, an engagement structure, a first lever arm, and a second lever arm, wherein the socket is configured for being inserted into an opening of an object from a first side of the object, wherein the first lever arm is pivotably attached to the socket in a first pivot point and the second lever arm is pivotably attached to the socket in a second pivot point, wherein the first lever arm is slidably connected to the engagement structure and the second lever arm is slidably connected to the engagement structure, wherein the fastening device is configured for being movable between a mounting position (P M) in which the fastening device is insertable into the object and a fastening position (P F) in which the fastening device is attached to the object, wherein the first lever arm comprises a first attachment surface and the second lever arm comprises a second attachment surface, wherein the first attachment surface is configured for engaging a first engagement surface arranged on a second side of the object in connection to the opening in the fastening position (P F), and wherein the second attachment surface is configured for engaging a second engagement surface arranged on the second side of the object in connection to the opening in the fastening position (P F), wherein the first lever arm comprises a first arm section extending between the first pivot point and a first arm end, wherein the first arm end is slidably connected to the engagement structure; and wherein the second lever arm comprises a second arm section extending between the second pivot point and a second arm end, wherein the second arm end is slidably connected to the engagement structure, characterized in that the first arm section and the second arm section are configured to be positioned in an X-like configuration in relation to each other in the fastening position (P F). wherein the first lever arm is pivotably attached to the socket in a first pivot point and the second lever arm is pivotably attached to the socket in a second pivot point, wherein the first lever arm is slidably connected to the engagement structure and the second lever arm is slidably connected to the engagement structure, wherein the fastening device is configured for being movable between a mounting position (P M) in which the fastening device is insertable into the object and a fastening position (P F) in which the fastening device is attached to the object, wherein the first lever arm comprises a first attachment surface and the second lever arm comprises a second attachment surface, wherein the first attachment surface is configured for engaging a first engagement surface arranged on a second side of the object in connection to the opening in the fastening position (P F), and wherein the second attachment surface is configured for engaging a second engagement surface arranged on the second side of the object in connection to the opening in the fastening position (P F), wherein the first lever arm comprises a first arm section extending between the first pivot point and a first arm end, wherein the first arm end is slidably connected to the engagement structure; and wherein the second lever arm comprises a second arm section extending between the second pivot point and a second arm end, wherein the second arm end is slidably connected to the engagement structure, characterized in that the first arm section and the second arm section are configured to be positioned in an X-like configuration in relation to each other in the fastening position (P F).