The laserson probe was a tool used for the modification or repair of electronic technology, including weapons. D84 described its capabilities in saying "it [could] punch a fist-hole in six-inch armour plate or take the crystals from a snowflake one by one". Taren Capel used it to modify the sandminer robots aboard Storm Mine 4 to kill humans. After Capel's death, the Fourth Doctor used a probe to deactivate SV7, stopping it from killing Toos. (TV: The Robots of Death)
The ancient cyborg Wesley Sparks threatened a number of people, including his fiancée Majenta Pryce, with a laserson probe. In the end an android version of Wesley plunges that probe into the cyborg's chest, killing it. (COMIC: Mortal Beloved)