From Liquipedia Dota 2 Wiki
Attacks against Sentry Wards cannot miss. Takes 1 damage from all attacks.
- Stacks with itself and
- When stacked with Observers, double clicking toggles the active ward type.
- Sentry Wards are permanently invisible and do not block paths.
- Wards have ground vision and cannot see through trees or the high ground above them.
- Cannot be placed within 1350 range of the fountain. Cannot be placed in the Roshan pit.
- Holding down + the item hotkey transfers a ward to an ally by clicking on them.
- Blocks neutral creep camps from spawning.
Commonly used to counter enemy Observer and Sentry Wards. Due to their unlimited stock, they are more commonly used to block neutral camps than observer wards.