Get the ALFRED lithium-ion battery packs and make sure that your smart locks keep functioning for a longer period. This rechargeable battery is designed for Alfred DB2S or ML2 series smart locks and it comes with a USB-C charging port to enable easy recharging when the battery runs low. It charges fully in approximately 4 hours and a single charge powers the battery to work for up to 12 months. | ALFRED Lithium-ion Battery Packs for DB2S/ML2 series