So. You may be wondering why I own a gas mask. The better question is, why don't you? How do you know when the air will suddenly be consumed by chlorine gas from the trenches of WWI? How do you know you will not need a trippy costume addition or essential bit of steampunk cosplay? Why haven't you bought this already?
From Evirstar Defense Products, "Designed to protect against nuclear, biological, and chemical agents". This does not include a filter canister, so this will not protect against anything. It just looks bizarre.