Russian surface-to-air missile. The 206 was a version of the 205 using a single-chamber Isayev engine in place of the four-chamber design of the 205. Cancelled in April 1953.
AKA: Berkut;La-206;S-25.
Development was begun in March 1951. The engine would also use a charged accumulator for tank pressurization. Further development was cancelled in April 1953 and the missile never entered the test phase.