Feature: 1. Suitable for both right-handed and left-handed golfers. 2. Easily attaches to the end of any golf club grip. 3. Projects a flat red laser beam during the swing to help monitor swing plane and identify positioning errors in real time. 4. Supports swing posture improvement and enhances consistency and quality of each swing. 5. Simple and intuitive to use. Specification: Material: Metal Size: 8.5 x 1.9 cm (3.34 x 0.74 inches) (Approx.) Package Includes: 1 x Golf Swing Corrector Plane Training Aid Product Usage and Features: 1. Attach the device to the club grip and swing to observe the projected red line. Use it to verify alignment and swing plane. 2. If the red beam points backward, the swing plane is too steep. If it points forward, the plane is too flat. When the beam points directly at the golf ball, the swing plane is correct. Steps: 1. Unscrew the battery compartment cover and insert one LR44 battery (battery not included). 2. Securely tighten the cover and attach the device to the end of the club grip.