COO reinterprets the traditional cuckoo clock in perforated metal rather than carved wood — a gently arched silhouette inspired by old Western architectural windows, bent from a single sheet into a semicircular form. Smaller circular cutouts pattern the face while a larger opening houses the cuckoo itself, creating contrast between the two hole sizes.

Also designed by Ryosuke Fukusada, it uses the same perforated-metal language as MOOV, with hour indexes aligned to selected cutouts. A two-step volume control and built-in light sensor automatically mute the cuckoo call at night, keeping the mechanism from becoming disruptive.