It sounds like you may be using the incorrect replacement lamp for your flashlight. D & C Cell Maglite Flashlights have different numbers of batteries or cells and therefore operate at different voltages, so each size Maglite Flashlight needs its unique lamp size. For instance, if you have a 4-Cell Maglite Flashlight and you put a 2-Cell or 3-Cell lamp inside, it will burn out very rapidly because the 4-Cell flashlight runs at a higher voltage than the lamp of a 2 or 3-Cell flashlight was designed to handle. For our personal size flashlights and your information, we manufacture a 2-Cell AA Mini Maglite Flashlight, a 2-Cell AAA Mini Maglite Flashlight, and a Single Cell AAA Maglite Solitaire Flashlight each of which requires its unique lamp... If you use the single-cell Solitaire lamp in a 2-Cell AA or 2-Cell AAA, the lamp will burn out immediately. Make sure to buy the correct lamp for your flashlight. It’s marked on the packages of our replacement lamps. If you are unsure of which lamp to use in your flashlight do not hesitate to contact us at 1 800-283-5562.