Any of the locators work the same way. A small map will appear in a box at the top right corner. A red square will appear on the map depending on the type of locator you use.
Though there seems to be a bug on this item, its still pretty useful for navigation as well as locating mines.
The Bug - The map at the top will not show anything except for the box's border when you go too deep (?) inside the caves.
Pages in category "Locator"
This category contains only the following page.