The Vexilar FL Digital Depth Indicator has a digital display that shows depth when combined with your current FL Series Vexilar Flasher (sold separately). As long as your flasher is on, the Depth Indicator will remain on. Easily connect the Digital Depth Indicator to the transducer cable from your FL Series flasher to get the depth reading instantly. The FL Digital Depth Indicator can also monitor the life of the flasher battery simultaneously simply by pressing a button. It even has the ability to sleep when not in use. No more worrying about your battery draining! Gives any Vexilar Flasher the ability to show a digital depth display Works with any Vexilar FL Series Flasher - even older Hondex, Si-tex, and Micronar FL-8's Displays battery life by pressing a button Easy installation and water resistant Display lighted for night time use Maximum Depth: 199 Feet Power Draw OFF: 124uA Power Draw ON: 21mA Made in the USA