They do not differ technically. These files exist in your theme directory and the template that loads is determined by the following: If you have a product with slug of dmc-12, then WordPress will first look for a file called single-product-dmc-12.php in the theme directory. If it finds it it will use that template when creating the page. If this file does not exist, then it will look for a file called single-product.php in the theme directory. If that file does not exist, then WordPress will look for a file called single.php in the theme directory.
