If you ask a professional home automation installation what they put in people's homes when it comes to X10 than the answer is always the same X10 Pro products. So you may ask WHY? I mean they look the same, they operate the same, they are made by the same manufacture but they don't cost the same. The answer is certifications. The X10 PRO line of products have a higher degree of certifications than standard X10 products. The X10 PRO line is verified by Underwriters Laboratory, Federal Communications Commission, Industry Canada and Canadian Standards Association. In addition the X10 PRO line is subject to higher manufacturing standards and because of this they come with a standard two year warranty.