Flip top caps come with foam pressure sensitive seals already inserted. However, you will need to check that they are pushed in/seated fully flat into the top of the cap and may need to adjust manually. If this is not verified, the seal may not be good and the seal may twist/deform.

Caps are designed to be used with pure honey.

Do NOT use these caps when using essential oils (citrus, mints, cinnamon, etc)  or flavor oils without testing a batch first!