Xlarge Easy Read Desktop Calculator 8 Digit Display 7.5" x 5.5" Calculators Include Battery No matter how you add it up, every desk needs a handy calculator! Battery-operated, plastic 8-digit calculators has easy-to-read number and function buttons, plus large tilt-up display. Avoid mathematical errors with this desktop calculator. AFFORDABLE/CONVENIENT, LARGE: 7 1/2" x 5 1/2" Lightweight: Weighs less than 5 oz Battery INCLUDED. How to change the small button battery: Just remove the eight small Phillips screws that hold on the back cover, slide the old battery out, insert the new battery and reattach the back cover. See pictures. Do the battery switch on a flat table, be careful not to dislodge the keys and align the holes through the circuit sheet before reinstalling the two screws that hold the circuit sheet in alignment with the keys. MPN: 18464 UPC: 639277046598 USA domestic shipments are shipped USPS Ground Advantage Mail with Tracking Reviews: Does what I need it to and slides under my monitor stand with the greatest of ease ... Got for my 66 yr old Dad who has clumsy big finger and gets frustrated with small calculators or even medium ones and say he'd rather use a slide rule. But he likes this big calculator.