Fuel caps?

Hi all!

Yesterday at a pay and play day out i discovered i had lost my fuel cap somewhere on site! Luckily i had one of those Emergency "Universal" caps as a temp fix (Doesent fit a defender without a skillfuly placed tie wrap!)

However i have just been pricing up fuel caps on the net and discovered that there are "Vented" And "Sealed"

What is the difference between them? Is it simply for the purposes of off roading such as wadind etc or is there more to it?

Thanks, Scott

Vented for for "normal" setup's

Sealed ones are for vehicles that have the roll-over "anti spill" kit fitted, which is just a kit with extended breathers on it which also has an anti spill trap, so if you turn over your truck (or operate it a lot at severe side slope angles) fuel won't spill out of the filler cap (As it's sealed)
but you NEED the breather kit with the sealed cap, otherwise you'll do about 10 miles before the engine cuts out, as it won't be able to suck the fuel out of the tank due to the vacuum in it.

Thanks alot mate thats a great help!

cheers, Scott