The WDSS is more expensive, but yields slightly better data because there is no possibility of friction in bearings. The WDSS mounts directly on the spinning beam, bypassing the pulleys. The WDSS requires that you use a computer or LabQuest with Bluetooth.
The Dual Range Force Sensor is less expensive, but yields almost as high quality data as the WDSS. The DFS mounts to the Dual-Range Force Sensor bracket that is installed on the right side of the CFA frame. Attach the Dual-Range Force Sensor to the Sliding Carriage via the Swivel Assembly (as mounted on the pulleys and Pulley Guide).
Use Photogate (VPG-BTD) to measure angular speed. It mounts to the Photogate Bracket preinstalled on the bottom of the CFA frame near the Encoder Wheel.