The M4A1-S | Mud-Spec is a Industrial Grade-tier rifle finish in Counter-Strike 2, originally introduced as part of The Anubis Collection when the Anubis Collection Package launched in April 2023.

The float range for this finish is restricted to 0.00–0.73, so Factory New, Minimal Wear, Field-Tested, Well-Worn, and Battle-Scarred are the only obtainable conditions on the open market. The restricted range is set by Valve at the time of release.

A Souvenir version is available, dropped exclusively from cases collected during Major Championship matches and stamped with that tournament's stickers. Active listings for M4A1-S | Mud-Spec are tracked across 18 marketplaces, with prices spanning $0.30 to $11.15 depending on wear, variant, and seller.