A Scarlet & Violet Build & Battle box is a product designed for players to get started with a new Pokémon TCG set, typically containing a ready-to-play 40-card deck with one of four unique foil promo cards, four booster packs, and a code for Pokémon TCG Live. The decks are ready to play but can be enhanced with cards from the booster packs, and the box often includes additional components like a setlist and deck-building tips. 
What's inside a standard box
40-card ready-to-play deck: 
Each deck is pre-built and includes one of four possible unique foil promo cards from the set, as mentioned on Pokemon.com and Pokemon Center. 
Four booster packs: 
These packs contain cards from the specific Scarlet & Violet expansion that can be used to improve your deck. 
One code card: 
This grants access to the same cards in the online version of the game through the Pokémon TCG Live client. 
Setlist: 
A checklist of all the cards in the expansion, often with deck-building tips, is included to help players. 
Key features and benefits
Beginner-friendly: 
It provides a quick and easy way for new or returning players to start playing with cards from the new expansion. 
Enhanceable: 
While the pre-built decks are ready-to-play, the booster packs allow you to customize and strengthen your deck for more advanced strategies. 
Pre-release events: 
These boxes are often used for pre-release events at local game stores, where players build decks from the boxes and then play in a tournament. 
Variety: 
There are typically four different versions of the box, each with a different foil promo card to encourage different deck-building options