The Esca® MS 102B Blue Fading lights are optimized to emit very specific wavelengths that mimic the predominant lure lights used by marine organisms. The Esc® blue is generally recommended for clearer and/or deeper water. The Esca® comes in a plastic case and a size 1/0 treble hook. The Esca® uses no batteries and generates its own energy in salt water. Attached to your favorite lure or tackle to catch more fish.