I am only using the main unit, so I will be selling the sub-unit. The battery was installed to confirm power-on. Operation was confirmed without any problems. The battery has never been fully charged, and the sub-unit has never been used, so the battery's potential is unknown. Model: Main unit: VE-GZ31 Sub-unit: KX-FKD558-W It will be shipped in the dedicated box shown in the photos. Thank you for your consideration.