Solar Panel for Early Version Stickup Cam with usb

I have an early version stickup cam (the flat black cam) with micro usb charging port. My Ring app keeps asking me to consider a solar panel. So, I went online to purchase one. But I cannot find a Ring solar panel with usb connector. I went to Ring.com help and saw a photo of MYcamera connected to a solar panel, so I assumed it would work. I purchased a panel but it arrived with a barrel plug. I wass expecting a usb connector or adapter. Panel says it is for Spot Light Cam. Item returned. I cannor find a Ring solar panel with usb anywhere. Does it exist? Is there a model or part number to refer to?