The Black Box Transom Kit consists of a piece of downrigger cable that can be mounted across the transom of a boat.  It allows boats without downriggers to use the Pro-Troll Black Box to attract fish.  
The Pro-Troll Black Box regulates the electrical field which occurs around a boat whenever it is in the water.  Most Black Boxes are used in conjunction with a downrigger.  Many boats do not have downriggers or are used in places like shallow rivers where downriggers are not needed.  The Transom Kit allows fishermen without downriggers to control the voltage around their boat.  A short piece of downrigger cable is mounted across the transom of the boat and is connected to the Black Box.  The result is that the fisherman can avoid voltages that repel fish and dial in the voltage that will attract fish.  The transom mount kit consists of two insulators for mounting on the transom, cable to stretch between the insulators and a connector wire which will plug into the Black Box.  For more information go to www.protroll.com and call up the Black box.