These are smaller versions of Kazō's Wooden Chakra Canister. When preparing them, he will infuse the same amount or more of chakra that he uses for the canisters. So much chakra in such a small space makes these canisters unstable. If punctured or if activated by Kazō, the chakra will burst out, causing the canister to explode. As the chakra flows into the shattered wood, it can be manipulated.