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Elements are the flexible elastomeric inserts, also called spiders, that are placed in between a Jaw or HRC coupling. These elements dictate the torque rating of the coupling, as well as the coupling's response to vibrations, temperature, chemicals, and speed. The commonly used materials in producing spiders are Nitrile Butadiene Rubber (NBR) and Urethane. NBR based elements provide the best damping capability and have an operating temperature from 212 to 240 F. Conversely, Urethane based elements have less damping capability but with a higher torque capacity and is suitable in 160 to 230 F operating temperatures.