Ⅰ. Built-in 210mAh battery with solar receiving board so it can be used without battery. Supports 12-digit large screen display which makes it more practical for use. With a smart shape and design, practical to use. Ultra thin, portable and useful. Compact, light weight and easy to carry. The calculator is made of eco-friendly plastic and electronic components, the bottom of the calculator has a non-slip gasket, which is not easy to slip during operation. Ⅱ. Size: Approx 10.3X18.5cm/4.05X7.28in; Color: Green/Red; Weight:185g/0.4lb; Material: ABS; Applicable Battery Type: Solar / Built-in 210mAh Battery; Operation Style: Capacitive; Type: 2.4Ghz Wireless; Application: Number|Desktop|Laptop|TabletKeyboard; Standard: Mini Keyboard; Language: English Ⅲ. Transition: 1cm=10mm=0.39inch. Please allow slightly 0-1cm difference due to manual measurement. Colors can appear different depending on light and how the listing is viewed. Thanks for your understanding and attention. Ⅳ. Package includes: 1 x Calculator