Light bulb with threaded, screw style base for use with 6-volt battery. Bulb socket and/or holder sold separately. Threaded bases are 9mm wide, bulbs are 22mm long. Product photo is enlarge to show detail.
Great for the lab, but wish they had lasted a few more experiments.
Review by Ellen
They were the perfect size for what I needed; wish they had lasted through the entire lab sequence. Also, please include the suggested voltage of batteries -- I had to play around a lot with this to get bright enough light.