Badge "For Extended Service".

[EricFG]

A little more info on the OP:
'Order of the Ministry of Defense of the USSR № 146 of August 1, 1957 was established for the three characters re-enlist: for the Army, Air Force and Navy. At the same time provided for a sign on all the time, by changing the suspension soboznacheniem's ​​long service.

Developed by artists sign the SMI Technical Committee and the USSR Ministry of Defense are produced at the Moscow plant "Victory."

With the end of the war and the beginning of the mass demobilization of the armed forces once again the question arose of keeping staff non-commissioned officers from capitulationists.
External manifestation of this was the order of the Chief of Logistics of the Red Army № 129 of November 26, 1945, by which sverhsrochnikam to be worn on all forms of clothing were introduced chevrons similar to those used in the Imperial Russian army.
In 1957 it was decided to give up the chevron and go to the badge with removable designated number of years of long service. Signs initially for prednaznachalit sversrochnikov, sergeants and petty officers, but they were also non-commissioned officers and warrant officers.

At the bottom there are two lugs, which with the help of adapter rings attached triangular suspension (label) with rounded corners and covered in black numerals "1 and 2", "3 and 4", "5 and 6." The extreme figures - "25 and 26." Изготавливался из латуни. Made of brass. The size of 38x60 mm. Fastened to clothing with safety pin.'