The towing lead is only for use with appropriate diving machine (electric or manual) with fishing rod and reel with steel cable. It is essential for allowing the trolling lures to sink at great depths and to have the artificial lures at a distance in several stages depending on the weight and speed of the boat, so you have the opportunity to fish with multiple lures and/or trolling rods. Ideal for trolling at height. Lead body and ring made of stainless steel AISI 304.