This is a skin for the Garage Door item. You will be able to apply this skin at a repair bench or when you craft the item in game.

This item was added to Rust but never sold in the item store due community feedback that the transparency was excessive and too pay-to-win (source). The item is technically accepted in-game and could be traded and sold on the market if you could somehow obtain a copy. There are currently no known instances of the item in existance as it was never sold in the store and does not drop from loot containers.