This is a ring to go under a 100g or 4oz isobutane fuel canister. It solves a couple of issues. First is it keeps the fuel canister from getting a rust ring in the bottom of your pot. It also cuts down on the rattle of the canister in your pot. And lastly it holds a mini Bic lighter in a clip so it doesnt bounce around. 

I printed mine in glow in the dark pla because why wouldnt you want it to glow in the dark?