DVKNM 4K RV Backup Camera System 10.36" Quad Split Touch Screen Monitor 4 1080P HD Rear View Cameras DVR Recording Bluetooth Music USB Video Play IP69 Waterproof Night Vision for Trailer RV Truck etc.Bluetooth & USB Disk: Connect the mobile phone Bluetooth,the monitor comes with its own tweeter Speaker,you can play music,built-in microphone for answer…