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Note that you have to click on a crate to pick it up.

[edit] Healing Crate

Will automatically repair any nearby unit that collects it.

[edit] Veterancy Crate

Promotes all nearby units one rank. Multiple units can be promoted by ordering them to collect the crate all at once, although they have to be near the crate itself.

[edit] Money Crate

Gives a $1000 bonus.

Computer foes that grab these get $2000.