An iliac branch device includes an iliac septum limb configured to be deployed in the common iliac artery. The iliac septum limb includes a graft material, a proximal end, and a septum. The graft material defines a common iliac lumen extending between the proximal end and the septum, the graft material and the septum defining an internal iliac lumen and an external iliac lumen. The iliac branch device including the iliac septum limb has several modes of adjustability. In addition, the iliac branch device has a relatively small cross-sectional area allowing the iliac branch device to treat relatively small iliac aneurysms in short common iliac arteries. This allows the iliac aneurysms to be treated at very early stages of the disease.