Ehhh??? Huh... Well, one way you could tell that you're getting a 3W carbon resistor, instead of a ceramic wire-wound 5W, is put an inductance checker to it. Look at it this way, at least you could probably use these on RF applications. But, still... Almost makes you not want to break open that carbon resistor, to find out just what's inside that. Hmmmmm, a piece of Tungsten???