How to find serial number location for ECHO Shred 'N' Vac

Where is the serial number or manufacturing number located on my ECHO Shred 'N' Vac?

ES-250:

This model will have one of the following locations:

With the unit off, look below the blower tubes on the fan housing side of the unit. The model and serial number are on a black and white or black and silver sticker attached to the housing. 

With the unit off, look below the blower tubes and next to the muffler. The model and serial number are engraved on the housing. 

The serial number will begin with the letter "P" followed by 11 numbers (Example: P33711001001).