Create custom routes in Umbraco

CustomRoutes.cs

public class CustomRoutes
{
    public static void Register()
    {
        RouteTable.Routes.MapRoute(
            name: "Product",
            url: "Product/{action}/{id}", // dont use {controller}
            defaults: new {
                controller = "Product", // dont skip this line
                action = "Index",
                id = UrlParameter.Optional
            }
        );
    }
}

Global.cs

// ADD THIS IN THE GLOBAL.CS FILE
// IF THE FILE IS NOT AVAILABLE CREATE ONE

public class Global : IApplicationEventHandler
{
    public void OnApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
    {
        // ADD THIS LINE TO REGISTER THE NEW CUSTOM ROUTES
        CustomRoutes.Register();
    }
}

ProductController.cs

public class ProductController : Controller
{
    public ActionResult Index(string id)
    {
        // create a view under /Views/Product/Index.cshtml
        return View();
    }

    public ActionResult Comments(string id)
    {
        // create a view under /Views/Product/Comments.cshtml
        return View();
    }
}