Retractable - Slide Button, Plastic Body,Plastic Clip,Plastic Grip,Plastic Grip,Adding and replacing refills with this pen body is a snap. The easy-open flip-top cap features a textured conical design that's easy to open one-handed. With the top cap open, you can simply drop a refill into one of the pen body's component slots.This pen body also features a translucent grip section that helps you see when your refills are almost out of ink.