Fight those dry lips! Never forget your chapstick again! ;) Features a long thread with a tight fit. You can use this container for geocaching, too! It should be watertight, when in doubt, just add a fitting rubber seal ring. It has a stable attachment for a keyring. I printed it multiple times, it always fits like a charm! I designed this for a specific product, but it should scale easily to the size you need for your purpose..