Is Sola Specials hentai?
No
Rated PG-13 (Teens 13 or older) on MyAnimeList and not tagged as Hentai.

Special · 2007 · 2 episodes · PG-13 - Teens 13 or older
Comedy, Romance, Supernatural
DVD-exclusive specials. The first takes place between episode 4 and 5 of the main series and and the second is a prologue to the series leading up to the events on the last day before the beginning of episode 1. (Source: AniDB)
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