Shimano Thunnus CI4+ Built tough for tough saltwater species, the Thunnus CI4+ range consists of four sizes from 4000 to 12000, which covers every inshore to medium offshore application imaginable. After freespooling a bait down to where the target species lurks, the BaitRunner function is engaged. The spool begins to spin as a fish is fooled into accepting the bait under near zero tension; you turn the handle, engage the main drag and… hooked up!