Clamp Retort - 4 Prong, Powder coated-EIS-CH0682 offers a thoughtfully designed, durable resource for hands-on learning. Steel retort clamp measuring approximately 9.75" in length Jaws are lined with cork to protect lab ware, and can open up to 3" in diameter Clamps are an essential material for lab apparatuses and setups Will need a boss head in order to attach to a lab stand Great for use in any chemistry or biology lab This retort clamp is perfect for holding lab equipment in place during delicate experiments. The four prongs on the clamp provide more points of contact, and the cork lining on the jaws gives the clamp a firm, yet gentle grip on precious glassware.