Rare Olivetti mechanical calculator from the 1960's, original turquoise body and purple bottom. Functional, very clean, no broken parts. This is the Summa Prima 20 model made by Olivetti Underwood, logo on top, hand engraved serial 398733. Blank name plates top and back. Italian manual in PDF format included. New paper roll and original ribbon included (ink is dry). Measures 5 X 7 1/2 X 11 inches.