1923 Mi.212a-214a, 1st May 1923 - Philately of the Workers - Surcharge bronze overprint 3 values: 1+1 ₽ - Russian ruble, 2+2 ₽ - Russian ruble, 4+4 ₽ - Russian ruble; Mi: RU 212a-214a; Sn: RU B38-B41;  Yt: RU 213-215;  Sg: RU 315-318. MNH Cat 450€