What is "gymnastyorka"

Gymnastyorka (usually translated in English as Gimnasterka; also spelled Gymnastiorka; ) was a Russian military shirt-tunic comprising a pullover style garment with a standing collar having double button closure. Additionally one or two upper chest pockets, with or without flaps, may have been worn. It had provision for shoulder boards (epaulettes or shoulder straps) and sometimes reinforced elbows and cuffs. The Tsarist version had the standing collar while the M35 version had a stand-and-fall collar which was replaced with the standing collar in the M43 version. The Soviet Army M35 version usually had hidden buttons. A double breasted version (kitel) for officers of all ranks existed during the Tsarist period.