When designing the ultra-thin "ThinKing" watch ("King of Thin Watches"), Konstantin Chaykin introduced a radical redesign of the mainspring barrel.

This carefully executed sketch of the device makes it possible to understand the main principles of its construction. The lower and upper barrel covers are eliminated, and their function is taken over by the movement’s mainplate and the barrel bridge. There is no separate barrel wheel, because its role is performed by the toothed rim of the barrel. The ratchet or friction clutch – four different versions of this device are shown in the sketch – is installed inside the barrel arbor.