The present invention generally relates to the field of transcatheter device closure techniques for closing an opening in a tissue and more particularly, to occlusion devices for closing anatomical defects in tissue such as defects consisting of an opening connecting a front side and a back side of a tissue. More particularly the present invention relates to occlusion devices for closing septal abnormalities such as atrial septal defects and patent foramen ovale, delivering systems for such occlusion devices, kits comprising the occlusion devices and the delivering systems and to methods of closing an anatomical defect in a tissue consisting of an opening connecting a front side and a back side of a tissue.