An apparatus for treating an aneurysm includes an occlusion element configured to be releasably coupled to an elongate delivery shaft and having a distal end, a proximal end, and a longitudinal axis extending between the distal end and the proximal end, the occlusion element configured to be delivered in a collapsed configuration and further configured to expand to an expanded configuration, the occlusion element comprising an inverted mesh tube having an outer layer and an inner layer, the outer layer transitioning to the inner layer at an inversion fold located at or adjacent the distal end of the occlusion element, the inversion fold defining an inner diameter, the occlusion element further comprising a maximum outer diameter, wherein the inner diameter is between about 35% to about 85% of the maximum outer diameter, and wherein an outer diameter of the occlusion element increases along the longitudinal axis to the maximum outer diameter.