Replaces the original bulb that came with the bulb. There was a problem with a flashing lightbulb, I replaced it and everything is fine with this replacement. I don't know how long they will last as this is the first time I have had to change bulbs of this size in this lamp. If they last as long as the ones supplied with the lamp they can last for years, it's hard to say at this time how long a replacement will last. Happy with the purchase.