The U.S. Patent Reform Act (Leahy-Smith America Invents Act: H.R. 1249-46) was signed into law on September 16, 2011. This act enables "virtual marking" of patent numbers associated with products, by providing a list of patent numbers together with their associated products on a publicly-accessible website.
The manufacturer’s patent search page for your particular product can be found by going to the internet address (URL) found on the patent label of your product. Be sure to enter the complete URL, exactly as shown on the label.