Camo Bloons popped by this tower permanently lose their camo status, and can be attacked by towers without camo detection.
~ Official Description
Signal Flare is the third upgrade on the second path for the Mortar Tower in Bloons TD 5. It costs $425 on Easy, $500 on Medium, $540 on Hard, and $600 on Impoppable. In Bloons Monkey City, it costs $750 normally and about $640 when favored. It allows the Mortar Tower to detect and attack Camo Bloons. In Bloons TD 5, the Mortar Tower cannot target Camos without this upgrade. When a bloon is struck by this upgrade, the bloon looses it's camo status and becomes a regular allowing all towers to freely attack it. In Bloons Monkey City, a perk from the Mortar Monkey's knowledge pack allows this upgrade to both drop the camo and regen property off bloons.