This is a skin for the Revolver item. You will be able to apply this skin when you craft the item in game.
The Revolver is cheap, prime for early game use. Although inaccurate, the Revolver's quick rate of fire allows it hold its own against players at most stages. Being a revolver, it has a low capacity of just 8 shots, but it's still an upgrade from its 1- and 2- shot alternatives.
Taking a Revolver to a fight against opponents with metal armor is quite risky, as such opponents will take many more shots than normal to take out (even more so considering the small capacity). It is best advised to only use the Revolver against opponents with similar armaments or as a sidearm to another weapon.