The ball is typically a size 5, which is the official size for adult matches and training.
While some Penta balls are standard match or general-use balls, others are specifically designed as weighted training balls (e.g., 600g or 1000g) used by goalkeepers to build strength and precision.
The specific ball in the image has a white base with red and blue accents and is noted as being waterproof in some product listings.