After the revolution after the Zsarist pogoni (shoulder boards) were replaced with a new type of rank insignia that was worn on the collar and known as Pilitsi. The collar patch insignia went through a number of designs changes until the outbreak of war with Germany when the Red Army went to battle on the 22nd June 1941 wearing coloured pilitsi but was soon discovered that German snipers could easly identify NCO's and officers so all ranks were issued with subdued pilitsi in August 1941.
The coloured pilitsi was usually worn in the rear especially by officers who had three patterns as shown below.

Although the pilitsi insignia was replaced by the Zsarist pattern pogoni in late 1943, many troops were wearing collar piltsi during and after the Battle of Kursk in July 1943 but was phased out from then on as most Red Army units were issued with the new Obr43 uniform and insignia. The pilitsi illistrated are for the gymnaistorka and represent infantry/Rifle arm of service with magenta backing with black piping.