This is a posable action figure from the Nendoroid series.
From the Good Smile Company website:
From the popular anime series and manga "Haikyu!!" comes a Nendoroid of the Karasuno High School Volleyball Team's 'Clever Blocker ' - Kei Tsukishima! He comes with three expression parts including a standard face, a serious face as well as a condescending smirk.
He also comes a variety of optional parts that allow you to recreate popular scenes from the series, as well as a volleyball and a base made in the image of a volleyball court. Headphones as well as his sports glasses are also included as optional parts. Enjoy the clever Tsukki in various different situations from the series!