Red LED tail light bulb fits most tail lights using standard 1157 bulbs. Twenty separate LEDs direct their light all around the circumference of the bulb and directly away from the bulb socket making this bulb suitable for mounting in any direction. Note: Overall length of the "bulb" portion (~39mm) is longer than a traditional 1157 so these may be too long for some lamp fixtures. The red LED color is correct for use behind a red lens. These lights are much brighter than your 1157 incandescent bulb, and the instaneous on catches the attention of the driver behind you. Not only that, they run on a fraction of the power.