Small, Medium, Large, X-Large
Saitama Green Shirt (Newest Shirt From Season 2)
Here comes the newest shirt in 2019, worn by Saitama in the very first episode of One Punch Man Season 2 along with the Oppai Shirt (to be purchased separately). In case you are wondering what does the character 毛 on the shirt mean, it means hair in Japanese. Judging by this outfit, it seems that Saitama is really fascinated with boobies and hair in his life.
Refer to the size chart here before you make your purchase.