In 1931 L. M. Ericsson put the cradle, the dial and the ringer inside a single moulded body. Bjerknes solved the mechanism; the painter Jean Heiberg shaped the shell. Bakelite decided the colour — Ericsson's own history says black was, for technical reasons, the only possibility, or perhaps some related drab nuances.

This system takes the object literally. The ground is high-gloss black moulding. Every card is a shell with a hard specular edge. The only circle on the page is the dial, the only warm note is the braided cord, and the only bright surface is the ivory number card behind the finger wheel.