pf2e.fyi
From Pathfinder Treasure Vault (Remastered), which isn't enabled.

Reef Heart (Greater)

ITEM 15
Price 6500 gp
Bulk 2
Category medium
Group skeletal
AC Bonus +3
Dex Cap +2
Strength +2
Check Penalty −2
Speed Penalty −5 ft.

This +2 greater resilient coral armor, often favored by allies of merfolk and aquatic elves, is made of living coral carefully harvested from the ocean depths. Legends speak of a variety of similar coral armors with distinct powers, but surface-dwellers know of reef heart as a magic armor that makes it easier for them to travel under the sea. Reef heart enables you to breathe underwater and gives you a swim Speed equal to your land Speed.


Activate (concentrate, manipulate)
Frequency once per day
Effect You cast a 7th rank Coral Eruption. If you conjure the coral underwater, it ceases dealing damage after 1 minute, but its duration is unlimited. If the magical coral remains in place for 1 year, it becomes non-magical coral from which a reef might grow.
Pathfinder Treasure Vault (Remastered)ORC