$1 1969-A Federal Reserve Note

this has a MISMATCHED

SERIAL NUMBER

in this instance, it is specifically the

D42/32XXXXXXB

error

this is a RARE MISMATCH 

an IMPORTANT and NECESSARY PART of EVERY "TYPE" 

COLLECTION of ERROR notes

mismatches are rather subtle, so most escape and enter circulation 

before being spotted--any high grade example is a genuine exception

mismatches occur in one of two ways: either the press operator fails to properly set the two independent numbering wheels in synch  (this generally reflects a mismatch at the beginning of the serial number) or the numbering wheel sticks on one side and continues to advance normally on the other

some mismatches have only one or two known, those are extremely rare and extremely valuable because of the few known; others have many known--which makes them perfect choices to serve as a examples of the error

some collectors attempt to acquire:

--one of each known variety

--one example from each denomination

--one of each type and denomination of FRN and SC including

   BOTH mismatched serial numbers and mismatched prefix/suffix

   letter

--one of different high-grade examples

--OR--simply one of whatever strikes the collector's fancy as     opportunity and resources permit

in particular, this example boasts:

affordability

This particular example has been independently authenticated and graded by

PMG

at the grade of

CHOICE FINE 15