Great replacement bulbs, and you can't beat the price.  These are for my under cabinet lights in my kitchen.  Check the wattage allowed on your light fixture to make sure.  I almost bought the 20v but thankfully didn't, because I hadn't checked the fixture beforehand.  I've only been using them for a month or so, so I can't give a review on longevity.  I will update the review at some point.