Simple operation confirmed. Currently working. A very old and valuable model. SHARP CS-2128 SOLAR CELL CALCULATOR Compete Around 1989, a popular model for certified public accountants. There is some wear and tear, and dirt. All photos are of the current condition, so please examine them carefully before bidding. [Notes] Please understand that there may be oversights due to a non-professional inspection. I am a non-professional packer. Boxes, cardboard, and cushioning materials are reused (recycled) items. * There are individual differences in how people perceive the condition of the product, so please understand that it is a "used item" that has been in someone else's hands. Those who are nervous or looking for a perfect item should refrain from purchasing. Product images may differ slightly in color and texture from the actual product, please understand.