The "Pokemon Hot Air Arena" (Japanese: Heat Wave Arena, SV9a) booster box is a Japanese-exclusive set from the Scarlet & Violet era that features trainer-Pokémon duos like Ethan's Ho-Oh and Misty's Psyduck. Each box contains 30 packs, with 5 random cards per pack, and is known for featuring special illustration rare cards, making it a highly desirable and collectible item. 
Key features
Set Name: Heat Wave Arena (熱風のアリーナ)
Set Code: SV9a
Language: Japanese
Contents: 30 booster packs per box, with 5 random cards in each pack
Theme: Continues the theme of trainer and Pokémon duos, with many popular characters featured
Notable Cards: Includes special illustration rare cards, trainer cards like Ethan's Ho-Oh, Misty's Psyduck, and Cynthia's Roserade, and powerful cards like Ethan's Typhlosion and Cynthia's Garchomp ex
Cards per box: 30 packs x 5 cards = 150 cards total