A PTFE stirring rod is a piece of laboratory equipment used to mix chemicals. It's thicker and slightly longer than a drinking straw, with rounded ends. A stirring rod is used for mixing liquids, or solids and liquids. Stir rods are used as part of proper laboratory technique when decanting supernatants because the contact helps to negate the adhesion between the side of the glassware and the supernatant that is responsible for the liquid running down the side. http://www.xieyinglabware.com/ptfe-labware/ptfe-stirring-rod/