Adjustable Settings: This adapter is a brand-new upgrade in terms of functionality and appearance based on the old version. The adjustable settings allow it to be compatible with devices that require 2-4 AA battery charging simultaneously, meeting your diverse device usage needs. No Need for Frequent Battery Replacement: This adapter is used to replace regular batteries and can provide continuous power to your devices. You no longer need to worry about the battery running out and having to replace it. Please note that dummy batteries require an adapter to work.