The Birdie in Sigh laser alignment hat is designed to help you line up your shot on the ball while increasing your focus and proper posture during your swing. Birdie in Sight™ assists in keeping your head and body in coordination with the ball throughout your swing, and ultimately will reduce slices and hooks to take strokes off your game. The built in Lasers are visible day and night. The battery is a standard CR 2032 and readily available where ever watch and key-fob batteries are sold. The lasers are easy to operate and will help teach you the fundamentals of proper golf posture and give you years of enjoyable practice and improvement.