Bought one of these little guys off Amazon for 20 bucks to tinker around with. My thoughts were it might come in handy occasionally when I drop the odd bolt somewhere in the engine bay never to be found again. Even has a little magnetic clip attachment for snagging things. I played around with it inside one of these exhaust I bought to see how well it works and to see if the online illustrations match the product.
The images look super clear. I bought one of those about four years ago when I was renovating a bathroom. I just could not figure out how the water pipes were positioned behind the tile wall in a shower area and I did not want to tear the wall out to see. So just a small hole and with the light on the tip of the camera I was able to see what I needed.