I use this one...it's feature rich, so many features that I forget how to work it sometimes. It's a looper and uses different sizes of micro SD cards for storage, which size depends on how much it can record of course. Slips off the window clamp easily to hide it when parked but the window clamp stays there. No fumbling with it. It does fall off when it gets too hot from sun though so you have to stick it back up there once in awhile.
The window mounting clamp device is usable for my sloped car window AND the nearly straight up and down RV window. And at only $25 per camera, I bought one for my car and one for the RV.
Window Cam!