Spreader Bars are trolling jigs meant to catch big game pelagic species of fish. They create a lot of splash and commotion on the water to lure the fish in where they see a school of squid behind the splashing. The straight back spreader bar runs in no particular direction, it will go straight back when trolled. Most effective run down the middle and far back. Every fishery is different, but in California it works best from 200-300 yards behind the boat. Trolling speed can range from 4-8 kn.