K-pop albums typically come in multiple versions. Each version contains the same music but has different photobooks, photocards, and packaging. Here is how it works and why.
When a K-pop group releases an album, the physical product usually comes in 2-8 different versions. The CD and tracklist are identical across all versions. What changes is the photobook (different concept photos), the photocards (random member cards), and sometimes the packaging design or poster.
Multiple versions serve several purposes: they give fans different visual concepts to enjoy, they create a collecting incentive (fans want all photocard sets), and they drive album sales since dedicated fans buy multiple copies. This is standard practice in K-pop and not considered unusual by fans.
POB stands for Pre-Order Benefit. These are additional photocards or items that are only available when you pre-order from a specific retailer. Different stores offer different POBs, which further encourages multiple purchases from dedicated collectors.