Brite-Strike UV Line Lights fishing lure lights are set at 385 nm (not visible to humans). They work best in very deep or dark and dirty water at any depth when there is a very little natural light. If you are using a UV coated lure or rig at less than 30 feet there may be sufficient UV light penetration from the sun. Brite-Strike UV Line Lights illuminators have a proprietary dye coating on the UV LED so that you can see a faint violet light to let you know it is on. Use either polished aluminum front version, flat white or flat black LAT (light absorbing technology) to match the type of tackle and conditions. Runtime: Up to 200 hours.