Review on 💡 Nite Ize Power Upgrade Flashlights: Enhancing Your Lighting Experience by Susan King

. When I bought it I thought the description said polarity didn't matter. must be for the other LED bulb I was looking at. When I put it in the flashlight provided, it didn't work. I just tested with battery and cable and it worked fine. I switched the batteries in the flashlight from one end to the other (inserted them upside down) and that solved the problem. I'm lucky I didn't burn out the LED bulb. I just can't forget reversed batteries the next time I change them. I only gave 4 stars because the description didn't say anything about polarity. The information anyone reading this should know is that the ground is positive and the metal case is negative. Unlike an incandescent bulb, polarity is important for an LED bulb unless it has circuitry to bypass it, which would make it more expensive. From the cost of this bulb you can see why I thought it had extra circuitry.