The Hellogeeks Pen v4 is a set of very cute and uniquely designed set of pens. The Hellogeeks Pens are 0.38mm gel black pen. Each purchase also includes one 0.38mm colored pen refill. The pen refill color is determined by the color of the body of the pen style. The Hellogeeks decoration is made of rubber material. Please check out the photos to learn more!