Eisco Labs Pendulum Clamp This sturdy pendulum clamp is constructed of an aluminum support bar with three screw clamps attached to a die cast head clamp for use on support rods to hang weights and pendulums. Can attach to support rods up to 16mm in diameter. Three screw clamps can securely and individually be used to attach weights with strings. This pendulum clamp makes it easy to simultaneously demonstrate or test the properties of simple harmonic motion in physics labs or classrooms. Overall length 11.5 x 1.5 x 1.25 inches.