Good construction

That's a good sentence. You could also say: The bulbs I found show what their wattage rating is, but it doesn't say how many lumens they have. Or The box said the wattage of the bulbs, but not the lumens. You may already know, but the lumen output will increase with increased wattage, but the exact relationship will depend on the type of bulb, design, etc. The wattage is an input and the lumen rating will be measured as an output using a standardized device that measures lumens under some standard conditions.