2 CDs (11 songs) + DVD (8/17 Yukata Matsuri Digest). Recommended song: M-01 "Ippan" with music video to be producedStarted on June 3, 2006. They have been in charge of the ending theme song for the TBS anime "The Chairman is a Maid" for 2 cool seasons. In 2014, they went on their first overseas tour "heidi. EU TOUR 2014 Fly high! On June 3, 2016, they successfully held their 10th Anniversary Live at Akasaka BLITZ. In October of the same year, they performed at the VISUAL JAPAN SUMMIT 2016 at Makuhari Messe, and in July 2017, they appeared at NipponCon, a convention in Bremen, Germany, where they have been accumulating stages both in Japan and abroad. On June 3, 2019, they celebrated their 13th anniversary.
