Advantage:This cool pens can not only make you the focus of the crowd,,pen spinning can also help to train your hands, eyes and cerebellum at some certain. Size:The size of cool pen is about 8.7 inches long, black ink, tip 0.5 mm round. Material:This spinning pens is made of plastic, which is safe and durable. Applicable population:For students looking for cool stuff, this cool office supplies is a good choice. This product is suitable for men, women, boys and girls, especially for unicron fan. This will be an exquisite cool office supplies. Customer service:If you encounter any problems after receiving the stationery pens, please contact us in time. We will reply to you within 24 hours and solve the problem for you.