The present disclosure describes implantable medical devices comprising covers, such as a balloon cover. Such devices can comprise a first layer of a porous polymeric material, such as ePTFE, surrounded by layers of a porous polymeric material having an imbibed elastomer, such as polyurethane. The cover can be used to assist in deployment of an expandable implant, such as a stent-graft, within the body of the patient.
