G&R Labs gives customers a credit on their present meter when they purchase a new G&R light meter. In many cases, an existing probe can be changed to work with a G&R Labs’ meter, saving the investment of a new meter probe. As an extra benefit, if you make the trade at a time when you are due for meter calibration, you receive the calibration as part of the upgrade. These meters are warranted for one year, with a warranty renewal every time the meter is re-calibrated.