This is a Allen Gun Sock known as the Tactical, model 13247.
Allen's Tactical Gun Sock is a silicone treated knit gun sock that is designed to fit scoped and non-scoped tactical firearms. Helps protect against rust" pitting" corrosion" and dust. Also great for preventing dings and scratches in storage or in transit.
Features:
Protects Firearm Against Dust and Scratches
Prevents Rust
Fits Scoped and Non-Scoped Firearms