The Laser is an item found at Link's Logic, which is located in the tropics area and is only accessible via the ferry.
The Laser can only be used with a Laser Detector. As a Laser Detector, it generates a signal output when detecting a laser. The Laser emits a red beam that is quite thin and does not hurt the player on contact. The beam being emitted can be blocked by the player or wood.
It is more effective to use a Signal Inverter when using a Laser with a Laser Detector as that means there will be an output when the beam is being blocked by an object. This can be effective in a scanning machine as there will be a signal telling the player when there is an object where the Laser is.