One task I used to dread was filling up my zero turn lawn mower with fuel. The safety spouts on today's gas can turn this into a very tedious process. I would have to constantly pull the spout out and allow air to flow back into the can to get the fuel to flow at a decent rate, up to a dozen times for 5 gallons of fuel. Well no more. Adding this little vent cap makes all the difference in the world. I only wish I had done it sooner.

MagicFour Gas Can Vent - https://amzn.to/3cxNMO6