HAPPY 7 DAYS

 is the 16th single released by 9nine.

CD

 * 1) HAPPY 7 DAYS
 * 2) SUMMER SUMMER SUMMER
 * Si, G, Na, L. (シ、グ、ナ、ル. )
 * 1) HAPPY 7 DAYS（Instrumental）
 * 2) SUMMER SUMMER SUMMER（Instrumental）
 * Si, G, Na, L. (シ、グ、ナ、ル. ) (Instrumental)

Limited Edition A DVD

 * 1) HAPPY 7 DAYS Music Video
 * 2) HAPPY 7 DAYS Dance Shot Ver.

Featured Members

 * Nishiwaki Sayaka
 * Satake Uki
 * Kawashima Umika
 * Yoshii Kanae
 * Murata Hirona

Single Information

 * Lyrics: Maria Okada
 * Music: CLARABELL