27 mm diameter, 5.86 g, 95% steel plated with 5% nickel, flat edge denomination "3 LEI" and oil refinery	inscription "REPUBLICA SOCIALISTA ROMANIA" meaning "SOCIALIST REPUBLIC OF ROMANIA", year 1966 flanked on either sides by a pair of squares, Romanian coat of arms

The edge of the coin is adorned with two wavy lines, separated by a five ray star.

In the monograph Monede şi bancnote româneşti (Buzdugan, Luchian and Oprescu, 1977) these coins are presumed to be made from nickel. It seems to be in fact nickel plated steel. The rust on the edge of the heavy worn coins is a good argument in support of the steel core, because the nickel is very resistant to corrosion.

All coins with year 1966 were released into circulation starting with year 1967. Officially, all communist coins introduced into circulation starting from the monetary reform of 1952 - so the 3 lei 1966 inclusive - mantained circulatory power until December 31st 1996. After this date all these coins were out of circulation, in conformity with the National Bank of Romania circular no. 33 from December 2nd 1996 (published in the Official Gazette no. 347/1996, 1st part).

In the book Monetele României (Coins of Romania, by Iliescu and Radovici, 2004, actually written in 1969) is mentioned that this coin was struck in 1967 - 1968 also, all coins bearing the same year 1966. Until 1968 8.477.000 coins were struck. It is almost a certitude that these coins were struck after 1968 also.

Below is presented a silver, proof-style, essay of 3 lei 1966, from the former C.C. colection. Only two such pieces are known.