Material: Nylon Size: 17*11.5Cm Color: Black Package Content: 1 Pcs * Training Alerter 1. Application: Through The Sound Of Our Golf Training Aid, Golfers Can Detect Their Left Arm Curvature Error In Order To Keep The Left Arm In A Straight Position; Therefore, An Effective And Desired Blow Can Gradually Be Formed; Suitable For All Golfers Or Golf Lessons, Especially Beginners. 2. Sound Prompt Incorrect Posture: The Golf Swing Trainer Is An Integrated Alarm Device Made Of Special Material That Immediately Generates A Sound When You Bend Your Elbow While Swinging. It Alerts You That You Are Not In The Correct Posture; You Should Adjust The Posture And Keep Your Left Arm Straight. 3. Adjustable And Easy To Carry: Strong Velcro And Buckle Make The Golf Training Aids Swing Adjustable, Easier To Put On And Take Off; The Thick Plastic Buckle Does Not Scratch The Skin Like Other Thin Metal Buckles; It Suits Most People'S Arm. 4. Not Easy To Change And Better To Warn: Compared To Other Suppliers Which Is A Simple Belt, Our Golf Swing Trainer Is Around The Entire Elbow, Ours Is Not Easy To Move And It Can Better Warn Golfers 5. Breathable Material: Our Golf Swing Training Aid Is Made Of High Quality, Breathable Nylon Cloth + Webbing + Velcro Fastener, Is Durable And Light; It Won'T Pressure You.