An endovascular stent graft delivery device has portion to remain outside a patient in use and a proximal portion to be introduced into a patient. The proximal portion has a dilator at the proximal end and a length extending module is fastened to the dilator and extends proximally. The length extending module has a proximal end which in use extends out of the patient. The dilator has a dilator marker and the length extending module has a first and second marker at the distal and proximal ends of the length extending module. The first marker and the second marker are at the same relative circumferential position on the length extending module so that the rotational position of the elongate body within the patient can be determined.