This device replaced the Sigaba and was developed in 1952. It was used for Secret-level communications and by NATO troops for interoperability with U.S. forces. The device has eight rotors with seven rotors moving in an irregular pattern. It was one of the early machines that had to meet ruggedness requirements. It also used a new technique for "on-the-fly" printing. The print hammer struck the paper while it was still rotating, but the type was still clear. The methodology was later used commercially.