Fullbottles are special items used in the Kamen Rider series, particularly in Kamen Rider Build. They are small, cylindrical containers that hold various substances, each representing a different animal or object. When combined, these Fullbottles allow the Kamen Rider to transform and gain unique powers, enhancing their abilities in battle. Each Fullbottle has a distinct design and color, often reflecting the creature or item it represents. The Kamen Rider can mix and match Fullbottles to create new forms and attacks, making them a central element of the series' gameplay and storytelling. Fullbottles are essential for the character's transformation and combat strategies.