Safe wheel, super fun. Crawl in it like a hamster, rock it back and forth, climb on it, bounce on it, the laughs and smiles are limitless. Sturdy construction, made of thick, soft and durable PVC material. Easy to inflate and deflate. Allows inflation with air pump, an electric pump is more efficient (not included). Recommended for ages 3 and up with adult supervision. Approximate dimension in inches when inflated 35″ outer diameter x 24″ width x 22″ inner diameter.