How much does Sentry Tower cost in AoE3?

400 wood, 200 coin, 60 seconds (AoE3: Definitive Edition 100.19.18309).

What does Sentry Tower do in AoE3?

Watch Tower: damage (Gun Ranged) +50%; Frontier Fortification: line of sight +5. The game says: "Towers gain a gunpowder attack, which inflicts more damage."

Technology

Sentry Tower

Sentry Tower (tech ID DESentryTower) is a technology in AoE3: Definitive Edition 100.19.18309 costing 400 wood, 200 coin, 60 s to research at the Battery Tower and Watch Tower. Effect: Watch Tower: damage (Gun Ranged) +50%; Frontier Fortification: line of sight +5.

Quick answers (3)

How much does Sentry Tower cost in AoE3?: 400 wood, 200 coin, 60 seconds (AoE3: Definitive Edition 100.19.18309).
What does Sentry Tower do in AoE3?: Watch Tower: damage (Gun Ranged) +50%; Frontier Fortification: line of sight +5. The game says: "Towers gain a gunpowder attack, which inflicts more damage."
What is the tech ID of Sentry Tower?: DESentryTower.

Towers gain a gunpowder attack, which inflicts more damage.

What it does

Watch Tower: damage (Gun Ranged) +50%
Frontier Fortification: line of sight +5

2 further effects (interface, visuals or AI) not listed.

Cost: 200400
Research time: 60 s
Game ID: DESentryTower

Researched at

Battery Tower

Watch Tower

Civilizations

Source: techtreey.xml and the Home City files, AoE3: DE 100.19.18309 (build 25040513).