Review on Pack of 4 Solid Coarse Thread Gas Can Caps by CM Concepts by Mark Fleming

The cap screws onto the bottle before the rubber seal comes into contact with it. Tried 2 rubber seals and still tight because as soon as pressure is applied to the seal the cap slips over the groove and pops out again. It is impossible to seal the most common plastic red lightning can. The Chinese are trying to copy the product again and can't measure or make anything work. It's a strong caveat (durability) and while it's probably 10 cents to make, $4 for $18 is better than $4 x $9 for each full replacement. Nonetheless. It's useless.