The Garmin Approach CT10 Golf Club Sensor starter pack (3) is a set of three small, lightweight sensors that screw onto the end of your golf club grips, designed to automatically track every shot (including putts) when paired with a compatible Garmin golf watch, providing detailed stats like distance, location, and accuracy to help you analyze and improve your game. This starter pack lets you begin by tracking your most-used clubs, like wedges and putter, with data syncing to the Garmin Golf app for in-depth analysis.