Atlas Copco rotary screw compressor, the Coupling Element (often called the "spider," "insert," or "buffer") is the resilient part of the drive system. It sits between the motor hub and the air-end hub. Because Atlas Copco machines often utilize a direct-drive configuration to maximize energy efficiency, this small component is responsible for carrying the full torque of the motor while absorbing the massive "kick" that occurs when the compressor loads and unloads.