[Easy to Use with Detailed Manual] Features include Monitor, Talk, VOX, Group, and Calling function. Adjustable volume, power switch, display screen too! This intercom system is easier to use than others with user-friendly and step-by-step manual! [Supported by Power Bank for Outdoor] This device is compatible with Power Bank (5V 1A) making it easy to take these intercoms any place you want. Besides, it designed with back hole for wall mounting.