Undeniably the best tool for measuring distance on a chart, dividers have been used for thousands of years without any significant changes until now. Outfitted with two built-in red LED lights, this indispensable tool takes on a new life. The 7 inch Light Dividers allow the user to read charts at night without losing night vision at the helm. The Light Divider also provides the right light for other tasks on board. Built into the legs of the device, the red LED lights are just the right intensity and distance from the chart so that no shadows are created on the chart by hands or other objects when turned on. Easily-adjustable mechanism allows for quick and precise one-handed operation. Runs on a small watch battery (included) which lasts for approximately 20 hours with continuous use. Battery can be easily replaced when lights begin to dim. Extra point, spare knob and lead included.