Q:  What is a PSP?

A:  The PSP is the very first model of the P7 line and is quite rare.  It looks like this:

psp.jpg (31533 bytes)

psp001.jpg (22616 bytes)

The PSP was produced from May of 1976 through 1978.  Only 239 total models were manufactured.  The serial numbers for the PSP go from 001-239, then 240-250 are for the PSP/P7, and after 251 starts the P7 series.