This android app makes it easier to get the check codes for all locations within the stock room.
This app is fully offline, so you never have to worry about having a connection to use it.
You will get this warning when you click on download, click on download anyway (highlighted above).
If you get the above popup after downloading the file click Settings (highlighted above).
Once you have clicked on settings you will see a screen similar to the above image, click on Allow from this source (highlighted above) to start the installation of the app.
Download here