Several years ago I installed a DD-100 digital depth and battery charge indicator on my Vex FL20 Propack. I thought I'd provide a quick review. The main lake I fish is 50+ ft deep, so the Vex needs to be set at either 20,40, or 60 ft settings, depending on lake depth where I am fishing. I also almost always use the bottom zoom feature. Whenever a buddy asked "what depth are you at", I was always frustrated because I had to get my cheater glasses out and go through the mental gymnastics of looking at the correct "depth ring" and adjusting for the fact I was using the bottom zoom. Anyway, the DD-100 solved all that, providing instant depth and a battery charge indicator. It might seem like a minor convenience, but I can't recommend it enough. My only question is why vex doesn't just add this directly on their factory units.