This is a set of clothes or accessories for figures.
From the Good Smile Company website:
From the popular volleyball manga series "Haikyu!!" come cute Nendoroid face parts cases based on the uniform colors of Fukurodani High School!
The cases allow you to store up to two spare expression parts inside while also having a cute appearance to put on display - which means that even your spare parts will have a place in your collection! Place your favorite face plates from Haikyu! Nendoroids or any other characters inside and enjoy their cute company by your side!
Note: Images shown here are for illustrative purposes only. No Nendoroid expression parts are included with this product. Certain face plates may not fit into the parts case depending on the character design.