These:
I have 2 of these.
I was so frustrated using the "Safety" caps. Whomever invented those should have to use them 50 times a day for the rest of their lives! [/rant off]
Mine sit under my deck rain/sun/snow for the last 6 years without issues. They are pricey now, but I would buy them again. The hose makes them easy to dispense fuel. Wide mouth easy fill. I put Stabil in before filling. Rotate around 6 months if I remember.
You can always get "for racing use" cans like the VP racing ones