Travelex calculator with currency exchange function. Approximately 4 x 7.5cm, light and small, convenient for travel. I think I haven't used it much, as it was given to me by a travel agency when my family traveled. Operation has been confirmed. I don't know how long the battery will last. - Brand: Travelex - Model: Calculator - No instruction manual. - Function: Currency exchange calculation - Of course, it can also be used as a regular calculator. - Country of Manufacture: China Thank you for viewing.