I love this tool! It is very simple to use - once you figure out how to do so because the directions need a microscope to read and are very, very sketchy, especially for we iPhone and Mac users. Thank you to those who helped supplement those directions. It turns out to be real easy - I speak only for Apple users here - just get the app from the app store, charge the battery (note the tiny green light which shows it is charging - off when charged), turn on the device, (optional but helpful at least for the first time) click into Airplane Mode in Settings, go to the phone and open Wi-Fi in settings, select Jetion_fd1fc106 as your source, enter in the password 12345678, open the app on iPhone, and there you go!To install one of the tools - the mirror, magnet or hook - you have to twist off the small lens cover on the probe - just unscrew it slowly and knows it will take a few turns to get it off, it is well threaded to keep whatever is threaded on there safe from just coming loose and falling off. When you put the tool away, be sure to put the cap back on because it has a nice transparent cover to protect the lighted probe.This is an amazing tool! Actually, it is the third one I bought - purchased two others for my son-in-law who is a cabinet maker. He loves it - and, poor sinner, uses the other phone operating system booo! lol.I ordered the supplemental mirrors, hook and magnet. The unit comes with a mirror, hook and magnet as well as some other tool, I have no idea as to its purpose. Is nice to have backups of those.Excellent product! Delivered on time and in solid box packaging. Only complaint there is Amazon once again shipped a piece of equipment throwing the box into a larger shipping box with no padding to keep it safe. This is becoming a habit I fear with Amazon. They usually do much better.