My exact model was discontinued and replaced with this one: https://www.lorextechnology.com/security-camera-systems/home-security-system-with-2-wireless-security-cameras/LW42W-1-p
But it appears to be out of stock. Mine is wireless, as in the signal. The cameras themselves need a power source.
They do make battery operated cameras, but those are pretty expensive. All the ones I have seen are motion sensored and not a continuous live feed. Battery life can range from 6 weeks to 3 months from what I've read.
I have a two camera Flir system by Lorex Technologies. The cameras are weatherproof, have 120' night vision capability, and comes with the DVR. I got mine on sale for $200. It was worth every penny when I saw a fox pacing the fence line to my chicken run.