This smooth, blue-gray stone is carved with stylized waves or rows of wavy lines. When you are in water too deep to stand, the charm activates. You automatically become buoyant enough to float to the surface unless you are grappled or restrained. If you are unable to surface—such as if you are grappled or restrained, or if the water completely fills the area—the charm surrounds you with a bubble of breathable air that lasts for 5 minutes. At the end of the air bubble's duration, or when you leave the water, the charm's effects end and it becomes a nonmagical stone.