Canon Data Memo DM-100 Includes instruction manual ⚠ Batteries are not included. 11cm x 7cm When opened, 11cm x 14cm I believe this is quite old. It was left in a home drawer for a long time. The outer box has paper yellowing. When I replaced the battery (CR2025) (photo 2), the functions such as world clock, clock, phone book, and calculator worked as indicated (photos 3, 4, 5, 6).