Box of 20. SnapNrack RL Universal Link assembly including Link bottom, Link top, Link column spacer, and springs. 
The SnapNrack RL Universal Link with the manufacturer part number 242-02156-USA is a component of the SnapNrack TopSpeed Universal Mounting System (formerly known as the RL Universal System) used for installing solar panels on residential roofs. 
Here's a breakdown of its features and purpose: