The Electro Sapper, or simply Sapper (Mentioned by the Sentry Operational Guide as FM/AM Ultra-Sapper), is used by the Spy to destroy an Engineer's buildings. The Spy selects the weapon, stands near an enemy structure, and uses the primary fire button to place a charge. Prior to placement, a white sapper outline appears on the structure, indicating that the building is in range to be sapped. Once the charge is placed, life will slowly drain from the building until it is destroyed. A sapped building will cease to function (sentry guns will not fire, dispensers will not heal or dispense ammo, teleporters will not spin). When a sapper is attached to one end of a teleporter, another sapper is automatically placed on the other end of the teleporter, if it exists. An Engineer can remove the charge with two hits from his Wrench, if an Engineer removes a Sapper from a teleporter, the Sapper at the other end is also removed. If another Engineer strikes the Sapper first, he can get an assist for the Sapper kill, and a Medic healing an Engineer can also score an assist in this way. Pyros equipped with the Homewrecker can also destroy Sappers in one hit if they happen upon them, but this happens less frequently, as Pyros receive no alerts regarding friendly buildings (Engineers can also get assists from Pyros in the same way they can from other Engineers). A small gauge is visible on the Electro Sapper when it is being carried. It serves no purpose other than for aesthetics, although the "meter" will rise if a Spy highlights a building to be sapped. The sapper has infinite ammunition and no discernible "cooldown" time. It is possible to repeatedly place Sappers on a building faster than an Engineer can remove them, but this tactic seldom works if there are other enemies around.
When you place a sapper on a building, a small box with information about the sapper appears in the upper left hand corner of the screen. This shows what building you are sapping, how much health the building has left, and how much health the sapper has. There can be only 1 building monitored in this way at one time, and the first building you sap creates the box. When an engineer hits a building with a sapper on it, you will hear a tone sound that indicates your sapper has been damaged. This is the same tone an engineer hears when a building has been damaged. Note that while you may hear a "clamp" sound when you deploy a sapper onto enemy equipment, this sound is not heard by other players. They do, however, see the sapper device, the sparks, and hear a hissing noise. The Engineer who owns the structures will receive a warning in his HUD and will be aware that a Spy is near his equipment. The Engineer also says a line of dialog that can be heard by himself and players near him: "Spy's sappin' mah sentry!" for a sentry gun, as an example. Also, when disguised, if you attach a sapper, your disguise slaps down his right hand in front of him (an animation unique to disguised Spies), which is visible to enemy players. A destroyed Sapper, by the "Destroy 3 0" command, only drops metal if it was attached to a dispenser, otherwise no metal is dropped. This method drops 9 metal, 3 for each piece of the sapper.
The Sapper deals 25 damage to buildings per second.
Destroys: Level 1 Building (150 health) in 6.00 seconds Level 2 Building (180 health) in 7.20 seconds Level 3 Building (216 health) in 8.64 seconds