Yasakani no Magatama

The Yasakani no Magatama (八尺瓊曲玉, Literally meaning: Eight Shaku Curved Jewel), is a green circular jewel. This jewel was designed to enhance the chakra of the holder. During the 3 year time gap Aporia found the jewel and infused into his forehead. Now he can channel chakra through it and use extremely powerful jutsu. This jewel is also liked to the different battle technology Aporia uses. Aporia has stated that the jewel also allows the user the ability to read minds and see chakra.

Weakness
If to much chakra enters the jewel at once then it will shatter but other than that it is indestructible. Although it was hinted that Aporia can destroy the jewel at will.