I always felt that the potions in vanilla are so useless despite being very fun to brew and tinker with. The problem is that they are non-stackable and once you drink them, they leave an empty bottle in place. Throwable potions have their use, but the normal, drinkable ones are very inconvenient.
Ender Flask aims to solve this problem. Through the dimensional ender magic, they allow you to store up to 16 charges of the same kind of potion in one flask! You simply use the crafting grid to fill or refill an ender flask with potions (or milk!) and use it as you would any normal potion.
There are two special enchantments that can be applied on the Ender Flask:
In addition to the above, the Ender Flask can be enchanted with Unbreaking and Mending as well.