I use a ProCatch Plus by Environmental Concepts. It shows which of the 6 basic colors fish can see at what depth and water clarity. It also tells you when to switch more toward vibration baits instead of sight baits. Also has a temp gauge. Works real well when visiting a lake you normally don't fish or when the water color has changed. Use one and you may be suprised at what a fish can actually see.
Give a man a fish, feed him for a day.
Teach a man to fish, he'll sit in a boat and drink beer all day.