Recommended flasher for 6 to 12 lamps - 252 (not included) Recommended flasher for 12 to 16 lamps - 183D (not included) Recommended switch for trucks pulling double or triple trailers and for vehicles that flash their hazard warning lamps regularly, or for prolonged periods of time Recommended flasher for 16 to 20 lamps 283 (not include) 7 wire harness Pilot light for turn signal and hazard warning 16 bulb capacity for hazard warning, 8 bulbs per side for turn signal flashing