The Tech Cannon Bunker is a neutral defensive structure that, when captured by an Engineer, is a superior version of the Tech Turret. Unlike the Tech Turret, it consumes some base power and cannot fire at enemies that are too close to it.
The Tech Cannon Bunker provides immense anti-armor defense at the cost of some base power. A great danger to every vehicle as long as the units don't move too close to the bunker, taking advantage of its minimum range.
The Tech Cannon Bunker is similar in functionality to the Tech Turret, as an upgraded version of the latter that is designed to defend from vehicles and is more powerful.
Similarly, Tech Cannon Bunker is not good at dealing with infantry, which makes it easy for a single Engineer to capture it from the enemy. In addition, although Tech Cannon Bunker has stronger firepower, it has a minimum range, allowing some commanders to quickly get the armored units like the main battle tank close to Cannon Bunker and destroy it in its minimum range.