The CEM P Elba planetary counterflow mixer completes Ammann's program of single-shaft and twin-shaft mixers. Depending on the type of Ammann planetary counterflow mixer, its capacity ranges from 375 liters to 6,000 liters and allows for 250 to 4,000 liters of compacted concrete.

This type of mixer is distinguished by an impeller that rotates around a vertical central axis and, depending on the size of the mixer, is equipped with 1 or more rotating mixing stars. Due to the offset rotational axis of the mixing stars, the individual mixing tools of the mixing stars form a kind of planetary path.