note ..... with todays expensive outdoor bulbs, fixtures, security sensors, motion sensors or dusk dawn sensors, you have a significant investment in your outdoor lighting, spot or flood lighting. if water enters the inner workings of your outdoor lampholder, it will very often destroy your expensive outdoor bulb(s), may damage or destroy your sensor, and sometimes trip your circuit breaker. this can't be good! moisture also contributes to the premature failure of the bulb base, causing the bulb to separate from its' metal (screw in) base, this condition leaves the metal base of the bulb in the lampholder as you attempt to remove the bulb. again, this condition is usually the result of moisture caused by atmosphere, rain, snow, gutter overflow, lawn sprinklers, etc. these rubber gaskets help protect your bulbs, shielding the entry point of the destructive moisture, fixture interior, and all the associated electronics that may suffer when you blow a bulb due to moisture. if you want to get it right..... first, determine the maximum wattage rating for the fixture and associated sensors, use the lower rating, usually around 300 watts but sometimes as low as 150, never exceed this maximum wattage rating, in fact, try to steer toward lower wattage like 50, 75, 100 watt outdoor bulbs. unless lighting a stadium, avoid the higher wattage bulbs that get very very hot, next, reduce exposure to the elements by pointing the lampholders down or out ->, not up. finally, use these gaskets to protect those expensive outdoor bulbs and lampholder fixtures. your bulb will deliver a longer service life and you will avoid repeated headaches. most outdoor fixtures and bulbs can tolerate a bit of moisture, but, as you may discover, less moisture delivers stunning service life, sometimes years instead of months .....