The SDC444XRNVE is a pocket calculator manufactured by Citizen that offers users a convenient and efficient way to perform mathematical calculations. It features an 8-digit LCD display, 2-key independent memory, full-function mark-up keys, reverse percentage, square root, and sign change keys, grand total and percent key, decimal position setting, and tax keys. It also includes an AC/DC adapter for easy use when a power source is needed as well as a battery backup system in case of a power outage. The SDC444XRNVE is perfect for everyday calculations as well as advanced calculations such as creating invoices and contracts.