Flasher Bulbs Bonus Pack (9 Bulbs): Mini Flasher Replacement Bulbs, Incandescent, 2.5 V, Up To 150 Lights Per Bulb 3 packs of 3 flasher bulbs, 2.5V Converts steady burning light sets into flashing sets Use with 50, 100 & 150 bulb sets (9 flasher bulbs will work with up to 1,350 feet of lights) Replace by hand, or, works with Lightkeeper bulb replacement tool