is an extended play CD released by girl idol group Berryz Kobo on December 7, 2005. It is the third of three releases issued by the band in the space of four weeks, along with their second album Dai 2 Seichà Âki and the ninth single "Gag 100kaibun Aishite Kudasai". "2.5" is pronounced në ten go.
The EP contains five previously released tracks in the aforementioned ninth single's A-side, plus four earlier single sides. Only one track, "Arigatà Â! Tomodachi", is exclusive to the EP.
Former band member Maiha Ishimura appears, but is not credited, on tracks 3 to 6.
The album debuted at number 45 in the Oricon Weekly Album chart, remaining in the list for 2 weeks.
The 9th single, , was released on November 23, 2005, by Up-Front Works' Piccolo Town label, as well as a version by Marvelous Entertainment, which featured a slightly different track listing. Abbreviated as "Gag100". It was later added on Special! Best Mini: 2.5 Maime no Kare. The song is used as the ending theme of Futari wa Pretty Cure Max Heart Movie 2: Friends of the Snow-Laden Sky. Due to Maiha Ishimura's graduation, this was the first Berryz Kobo single to feature only seven members.
The song charted at number 19 on the Oricon Singles Chart.