I replaced a transformer from an unknown brand of low voltage 12 volt rock lights last year which had probably been on the wall for almost 15 years. It finally burnt out. I replaced it with a 20watt one as it was compatible with any 12 volt system. It worked absolutely fine, I am only running x3 5 watt LED bulbs off it, well within the limits and I have had no problems so far one year later. When the other original transformer finally gave up the ghost this year, i replaced it with a Lumena transformer too. Another set of similar 12 volt outdoor lights also had a failed transformer from the original fitting. I replaced this with a generic one from tool station. It lasted barely a year!! The lumena are IP68 rated and I hope they give me as good a life as the original transformers. I would recommend them on the basis of a years operation.