Tools are used during room exploration. All tools and their quantities are displayed at the bottom of the screen. If you don't have the tool you want, buy it by tapping the plus sign next to its image. The research timer will be paused while you complete the purchase.
Of course, all tools are useful, and each in its own way.
— Pointer
Shows the location of the desired item in the room.
— Bomb
Removes 3 search items from the room.
— Compass
Will highlight the items you are looking for when you hover over them. Lasts for 30 seconds.
— Exorcist's Lamp
Eliminates any phenomenon for 30 seconds.

During the tutorial, some tools can be used an infinite number of times. This will be indicated by an infinity (∞) icon. In the future, using tools will decrease their amount in your inventory.