I have two "universal" cans from a major auto parts company that always leaked under the caps where the hose's barb screwed in. You could also hear the lids being screwed onto the jar and leaking through the o-rings. if the covers are not tightened with a wrench. A friend has a VP Racing jug and everything is sealed. When one of my original lids broke I decided to try these. They even work perfectly on my "nameless" jug.