This is the worst squonk bottle I have ever used. Even the cheapest I had in the past ( $2 per 5) made in China is much better quality than this one. The thread is is plastic actually an extension of the bottle which does not hold the cap on the place firmly. The tube inside is sliding too easy that cause a lot of problems inserting the bottle into the mod. Very disappointed with my purchase. Most likely will be returning it for refund.