montgomery p200Model: Montgomery Ward P200 (TXI-8662A)
Battery:  3*AA NiCd or 4*AA Alkaline

Adapter:  AC9130 or AC9120
Year: 1974
Chip: TMS0601
 The P200 could be easily identified as a close relative of the TI-2550. Both calculators use the same electronics, the same layout of the keyboard and even an identical mold for the housing bottom. The different look is achieved through a new mold for the upper half of the housing and a different style of the memory keys. The color of the housing is slightly different, too.