RAM : 9,5kb / 9,5 kb with RP-8 extension memory.  Released probably in 86, two years after the last of the series, the PB-220 gives up the wallet format that was becoming obsolete.  Programmable in Basic,with 1504 steps and accepts extension memory RP8 to offer 9 696 steps  Like four-operation calculators, it has the four famous memory keys : MC, MR, M+ and M-  The chracter set is the one of the PB-110 : no F KEY but MEMO functions and Shift+exe combination.
The PB-220 has then been released with the name PB-220G: it's the same machine sold with extension RP-8. Only the box has been redesigned. A small addendum was added to the doc :