Manning Manufacturing was formed while I was fishing at night, trying to measure the BIG ONE. While every fishermen knows that trying to measure your fish with a flashlight or any other light source is quite the battle. You always are either dropping the light, trying to get it at the right angle to see the ruler, the measuring device won&＃039;t stay still, and the fish is flopping around. That&＃039;s when I thought, "Why isn&＃039;t their a ruler that is mounted, and is illuminated ?" So after a lot of field testing, I came up with this model. It is just what us fishermen need, and best of all, it is mounted to your boat or you can carry this around in your tackle box so there is no time to waste when the "Bite is On!!" BENEFITS Boat Mounted 12VDC Illuminated Ruler Portable-Battery Operated Model 6 Volts Unique design illuminates ruler without causing "Night Blindness" No more juggling with fish and a light at the same time Compact low profile design, made by fisherman for fisherman Simply Amazing At Night!! Illuminates area around ruler to double as a courtesy light Surface stay&＃039;s cooler during the daytime than metal or aluminum rulers High quality. Built to last. Made with 100% durable acrylic, marine grade wire, stainless steel mounting screws, super bright low power LED