UDR is an error that can be found on the stems of some Pez dispensers. It is an abbreviation for "Upside-Down R."
Information About UDR
The UDR error is based on the registered trademark symbol (®) that can be found after the word PEZ on each side of dispenser stems. When this error is present, the R in the circle is upside-down on the side of the stem where the letters read from bottom to top. This is presumed to be an error with the mold that produced the stems.
The UDR itself can be considered a variation of the "registered trademark" symbol.
Approximately from 1990 to 2008.
UDR only appears on dispensers with regular feet (not thin feet).
Patents & Countries
The UDR error can only be found on dispensers made in Slovenia, with a 4.9 or 5.9 patent.
It is possible to find UDR on all stem colors.