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.
Going around the forum and saw my post about this phone boroscope. Well it saved my butt big time this spring. I was doing some work on my VW with the webbers off and dropped a lock washer. Couldn't find it. Got out the boroscope and sure as shit the washer fell down the intake manifold. Even worse that intake valve happened to be in the open position so the washer went right into the cylinder. I was eventually able to get it out. If I had just written off the washer as lost in the engine bay I'd have been replacing a lot of expensive parts.