Mass production aside, there is likely little input protection (thermistors, power resistors, HRC fuses etc) on that device... not an issue when checking wattage with the clamp, but I would avoid testing anything other than low voltage systems through the leads. Certainly wouldn't go probing three phase power circuitry as there's a high probability it will blow up in your face. Build quality and drop protection will be non-existent and the leads and accuracy will also be naff--these points are what typically contribute to a meter's expense, along with sound input protection. But as long as you're happy and avoid measuring mains voltage, then ????