There are generally two formats for the Serial Number, depending upon when the unit was manufactured.
Prior to 2007, all models generally had a 6 or 7-digit serial number (possibly alphanumeric) whose first two or three digits corresponded to the Model letter and number (without the 'VZ').
For example:
a model VZ-8plus� had serial numbers starting with "08..."
a model VZ-C32 had serial numbers starting with "C32..."
Starting in 2007 (the beginning of 2007 for VZ-8light�; the latter half of 2007 for other models), most units have a 7-digit, completely-numeric serial number starting with "100..." or "101..., etc...".
Desktop Visualizers have the serial number on the bottom of the unit, stamped on a small metallic label, under a bar code.
The serial number can also be determined from the On-Screen Menu (see below).
Model C12 and C32 Visualizers have the serial number on the bottom of the unit, stamped on a small metal square, under a bar code.
Model Eye-10 and Eye-12 Visualizers have the serial number under the bar code on a label on the underside of the unit.
Since mounted Visualizers are not likely to have the external serial number in a visible position, the On-Screen Menu should be used to determine the serial number (see below).
The On-Screen Menu of all Visualizers can be used to determine the serial number.
The serial number is listed under the Advanced Settings menu.
At the bottom of the menu, there is an entry "Ser. Nr.: ..."
On newer models, the serial number listed on the menu may have a leading zero (making an 8-digit number starting "0100..." or "0101..., etc.". You may leave off that leading zero, and give only the final 7 digits.
For older models, (ones that do not begin with "0100..." or "0101..."), the leading zero is significant and should be included when giving the serial number.
If the above methods are not available for determining the serial number, it is possible to get the unit serial number from the original shipping package, which has a label with the serial number on the exterior of the box.
However, this is not fool-proof method for determining the serial number (as errors in packaging can occur). Also, if you have multiple units at your site, it is much less error-prone to obtain the actual serial number of the unit in question from the unit itself.