Distance Requirements Short Indoor Mode: The distance from the tee to the FlightScope sensor should be exactly 8 feet. For the most accurate measurements in this setup, there must be at least 8 feet of ball flight. Indoor Mode: The distance from the tee to the FlightScope sensor should be 11 feet. For the most accurate measurements, there must be at least 13 feet of ball flight. Environmental Requirements Please ensure that there are no obstructions between the FlightScope sensor and the tee. Ideally, fluorescent lights should be avoided; incandescent, halogen or sodium lights are acceptable. If the location has fluorescent lights, aluminum insect screens available from any hardware store (Lowe's or The Home Depot) can be used to shade the lights. Metal Stickers or RCT Balls - Direct Spin Measurement (indoor only) Due to the short ball flight distance in an indoor golf swing simulator setup, FlightScope requires that the ball be marked with a metal sticker to get accurate spin readings. Only one sticker is required per ball. The golf ball is placed with the sticker facing the screen, away from the clubface. You are also able to use the Titliest RCT balls to measure the spin accurately, with no metal sticker required.