The reading depends on the plug-in element being used.
For example, if you have a 100 W element, you use the corresponding scale that ends in 100 (the bottom numbers on the display).
Similarly if you have a 10W element, you also use the same scale as the 100 W element but just move the decimal point (100 W to 10.0 W) for the correct reading. A 1W element also uses the same scale but move the decimal point two places to the left (100W to 1.00W).
If you have a 5W, 50W or 500W element you would use the scale that ends in 50 and if you have a 25W, or 250W element use the top scale.
