The SKS is a Soviet semi-automatic rifle chambered for the 7.62x39mm round, designed in 1943 by Sergei Gavrilovich Simonov. SKS-45 is an acronym for Samozaryadnyj Karabin sistemy Simonova, 1945 (Russian: Самозарядный карабин системы Симонова, 1945; Self-loading Carbine of (the) Simonov system, 1945), or SKS 45.
The Sks is a scaled down version of the PTRS-41 anti-tank rifle also designed by Simonov. The Soviets rather quickly phased the SKS carbine out of front-line service, replacing it with the AK-47, but it remained in second-line service for decades. It remains a ceremonial arm today. It was widely exported and produced by the former Eastern Bloc nations, as well as China, where it was designated the "Type 56", East Germany as the "Karabiner S" and in North Korea as the "Type 63". It is today popular on the civilian surplus market in many countries. The SKS was one of the first weapons chambered for the 7.62x39mm M43 round later used in the AK-47.
In total, SKS rifles were manufactured by the Soviet Union, China, Yugoslavia, Albania, North Korea, Vietnam, and East Germany (Kar. S) with limited pilot production (Model 56) in Romania and Poland (Wz49). Physically, all are very similar, although the NATO-specification 22 mm grenade launcher of the Yugoslav version, and the more encompassing stock of the Albanian version are visually distinctive.
Today the SKS is in service with Cambodia, Laos, China, North Korea and Vietnam, as well as many other countries in Africa.(Full credit to Wiki)
This batch of rifles is from Yugoslavia and are in good working condition.