M4A1-S | Mud-Spec by SayChains appeared in CS:GO on April 24, 2023. It belongs to The Anubis Collection, containing 19 weapon finishes themed after the same-named map. This collection was added to the shooter in the eponymous update.

Most of the carbine's surface is covered with dark gray paint. Brown and dark brown spots are applied to certain areas of the surface, forming a camouflage pattern that is effective in rugged terrains without vegetation.

Float Value of M4A1-S | Mud-Spec can vary between 0.00 and 0.73, allowing the skin to be obtainable in any exterior quality category. As the weapon’s condition deteriorates, it significantly darkens, causing the camouflage pattern to become less distinguishable. There are no wear marks visible on this skin.

M4A1-S | Mud-Spec is categorized as the “Industrial Grade” rarity and is available in a souvenir version.