Range-Finder IT REALLY WORKS!! Measure distances from your device to a Target! Works best on distances less than 500 meters. How it works: - Aim a Target and press A button. - Walk to left or right at specific distance (default 6 meters). - Aim same target again and press B button. - The estimate distance and altitude of target will appear on your screen. Use it with confidence in the field or at your favourite activities. Warning! - For accurate results, don't shake your hands while aiming the target. - Have a clear view of the sky to achieve better GPS signal. - Walk exactly distance to left or right. You can calibrate any time from settings panel.