The clip is designed to hold the Go Direct^® Force and Acceleration Sensor (GDX-FOR) in place when using the Centripetal Force Apparatus Moment of Inertia Accessory Kit (CFA-MIK). The sensor rests on this clip and rotates with the shaft to measure angular velocity.

Go Direct Centripetal Force Apparatus, Troubleshooting and FAQs
How do I attach the Go Direct Force and Acceleration to the Go Direct Centripetal Force Apparatus when using the Moment of Inertia Accessory Kit?