Fundamental Coefficient of Friction Grips employ a pulley and string mechanism to measure the force required to pull a friction sled over a material specimen. They are suitable for meeting a variety of material testing standards, including ASTM D1894 (plastic film), TAPPI T542 (paper and cardboard), TAPPI T549 (non-fibrous materials), and TAPPI T816 (corrugated). The upper grip is not included.