Chakra Lantern Wick
The amount of oil in a standard Chakra Lantern can safely hold 100 EP of chakra, and an exploding Chakra Lantern does damage equal to twice the amount of EP still stored in it.
A secret seal developed by the Kyoudo clan that acts as a tenketsu (Chakra Point) for a medium capable of retaining the energy, usually oil. By placing this seal on a thin sheet of linen and rolling it tightly into a “wick”, this allows for the creation of Chakra Lanterns.
Care must be taken when “charging” a medium not to exceed its ability to retain the chakra, as the “Chakra Point” works both ways, allowing the medium to also empty itself of chakra (as oil is naturally aligned with fire elemental chakra, this often has explosive results).
There is an entire school of secret techniques based around manipulating the chakra stored in media through the use of chakra wicks.