WOW, I'm running one, don't know why they told you it doesn't have one on it. Right at the top where the lid screws on, do you see an indent just above the threads? The is where the o-ring goes. If it ain't there, you got me what the difference is betwen ours, or I should say, why they are different.....If you do see the indention, go to Lowes and try to match up the dia. on the canister. (which is 11" dia) so you'll need one slightly smaller.