Euclid's C-Finder

Euclid's C-Finder is a unique weapon in Fallout: New Vegas.

Background
Father Elijah searched for this weapon, stating that someone must have scavenged it and sold it on the Strip. Sarah Weintraub mentions that she had it at one point, but sold it to a man wearing a strange collar. Currently, a child named Max is in possession of it, using it as a toy, chasing another child, Stacey, around Freeside with it.

Gameplay
The C-Finder is a handheld rangefinder linked to an orbiting laser weapon, the ARCHIMEDES II. Firing Euclid's C-Finder will result in a five-second delay and an animated sequence on the weapon's display before the impact. Euclid's C-Finder is not influenced by the player character's Energy Weapons skill.

Pressing the trigger constitutes firing the weapon, which will alert nearby enemies. The weapon can only be used once every 24-hours in-game, and does not work indoors. Euclid's C-Finder can fire a total of about 3995 times from full condition before breaking.

Location
In Freeside, outside of Mick & Ralph's, the player character can find Max during the day. The player character can pay Max 1000 bottle caps, or 20 bottle caps with a Barter skill of 45 or more. Otherwise, the player character can wait until Max goes to bed, usually after 9 pm, then pickpocket the weapon from him, resulting in a loss of Karma.

Related quests

 * That Lucky Old Sun: In order to use Euclid's C-Finder, the player character must complete the quest and choose to direct power to ARCHIMEDES II at the end of the quest. If the player has already completed that quest without directing the power to ARCHIMEDES II, the C-Finder cannot be activated.

Behind the scenes
The name Euclid's C-Finder, and the graphics it shows the player while it is operating, are a reference to using Euclidean geometry to find the third point, C, of a triangle, given points A and B, and distances BC and AC. In this example B is the player's position on the ground, A is the position of the ARCHIMEDES II satellite, and C is the position of the target.