Power supply type: AAA alkaline or NiMH rechargeable batteries; Number of batteries: 4; Battery life: About 170 hours (when using alkaline batteries); About 100 hours (when using Ni-MH batteries); Menu display 5 minutes, arithmetic 5 minutes, continuous use of cursor flashing display for 50 minutes. Size (D x W x H): 7.4 x 3.5 x 0.7 inches (188.5 x 89 x 18.6 mm); Weight: 8.1 oz (230 g).