The second single of popular voice artist/singer Aika Kobayashi. Continuing from her debut single "NO LIFE CODE", Mr. Tomokazu Tashiro of Q-MHz is in charge of total production of this single. The title song "Tough Heart" is an ambitious work which all 4 members of Q-MHz came up with an idea and completed it with all their efforts. In addition to the title track "Tough Heart", it will contain 6 songs including 2 new songs and their instrumentals.