The tower is a neutral structure which grants a greater viewing area to units that activate it; it can only be activated by ground units.
Burrowed and flying units cannot activate a watch tower but cloaked units can. Auto-turrets cannot activate a watchtower as they are Structures.
The visual radius (22) is greater than that of an observer (11, 16.5 deployed).
These are usually placed in strategic areas.
A player can quickly tell what an enemy is attacking with, making upcoming battles easier and blunting the effect of rushes.
A player attempting a rush is advised to try to hide rush attacks.
If units from two opposing teams are in control range (2.5) of a watch tower, neither will have control over it.
Watch towers are highlighted on the mini-map with an eye icon, visible as soon as play starts.
Watch towers are selectable structures but have no hit points (like mineral fields and geysers) and have only the "structure" attribute.
↑That particular screenshot mentioned shows off a visceral fight between Marauders and Immortals. North of the Immortal, you can also see the new model for the Xel'Naga observatory, though I'd have to say it looks much cooler animated. When it activates, it illuminates and crafts itself together to form a powered watch tower. Karune. 2008-11-19. screen from blizzcast 6, something strange. Battle.net StraCraft II General Discussion Forum. Accessed 2008-11-19.
↑ 7.07.1Xel'Naga Watch Tower only can be activated by the ground units.
Infested Marine can activate the Xel'Naga Watch Tower but Auto-Turret can't. Cyrda. 2009-04-22. Do the nighthawks have true sight?Battle.net StarCraft II General Discussion Forums. Accessed 2009-04-22.
↑No, at the moment burrowed units do not activate Watch Towers. Neither do flying units but invisible units like the Dark Templar or a cloaked Ghost will activate them. Xordiah. 2009-03-23. Watchtower Question. Battle.net StarCraft II General Discussion Forum. Accessed 2009-03-23.
↑ 9.09.19.2The Xel'Naga Watch Towers have larger sight range than Observers, but do not offer detection. I definitely wouldn't say they are inferior, as they have crucial uses throughout the game, especially in the earlier tiers. With only a SCV/probe/drone, a player can activate a watch tower, letting you know when the enemy is coming to attack you and with that. This alone, could easily change the outcome of any early skirmish battle that happens. Karune. 2008-09-16. Karune, i have a question about observers. Battle.net StarCraft II General Discussion Forum. Accessed 2008-09-16.
↑The Xel'Naga Watch Towers do not grant 'detection' of cloaked units, nor does it move around like an Observer. Thus, if that pack of Dark Templars come storming into your base and you have all your probes gathered around that watch tower, it's not going to do you any good... Karune. 2008-09-16. Karune, i have a question about observers. Battle.net StarCraft II General Discussion Forum. Accessed 2008-09-16.
↑Does these watch towers mean the end of proxy rushes? :(