Russian Empire. The breastplate "The pioner (Scout) of the 1st category" in a cavalry. It is approved on June 11, 1891. The sign awarded the lower ranks consisting in the teams of pioners in a cavalry and the Cossack troops. The sign type-setting of two details - a board and crossed a saber to a checker. Very rare.
Fastening is lost. The oxidized white metal. 34*34 mm.