PSI-1 Performance Sonar Interface for LiveSight(TM)Features:Track lure and fish movements in real time with a wider coverage area and at greater distances; targets stay in the LiveSight(TM) Sonar coverage area longerCombine the advantages of CHIRP Sonar (to view enhanced fish targets) with LiveSight(TM) sonar (to track lure and fish movements)LiveSight(TM) sonar coverage features a greater range: track shallow-diving crankbaits as far as 60 feet away and Alabama Rigs as far as 80 feet away HDS Carbon and NSS evo3 require a Performance Sonar Interface (PSI-1) module to work with the LiveSight transducer