4 sets x 6 car consists to be introduced by 2023, on the Skytree/Nikko/Kinugawa Lines. Slated to become the flagship of the fleet. Will be built by Hitachi Kasado.
https://tetsudo-ch.com/11937581.html
Tobu press release:
https://www.tobu.co.jp/cms-pdf/releases/20211111115910j-Hxsy54wjgySVaKcD-UrQ.pdf