Coiled whisks are shaped like a hollowed-out spoon.
They consist of a rounded bar frame, open in the middle, with a single spring coil wound around the bar.
They are good for small amounts of liquid in small vessels, in which a larger sauce whisk either wouldn’t fit, or would be overkill for the amount of liquid being beaten.
AKA “spiral whisks.”
The French call this whisk a “cuillère mini-fouet” (and sometimes, a “fouet à spirale.”)