The Knight skins are painted solid black and are adorned with gold lines on several parts of the gun. The design also features a counter-terrorist logo located above the magazine. There is currently only one skin in this collection, and it is M4A1-S | Knight. The skin was released on July 1, 2014, and belongs to The Cobblestone Collection. The skin is obtainable from various Souvenir packages. The skin comes in only two exteriors, Factory New and Minimal Wear, and has the Souvenir option.
As for the price of the Knight skins, the basic versions seem to outvalue the Souvenir ones, costing as much as $2000.
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