Omega Speedmaster is a line of chronograph wristwatches produced by the Omega Watch Company. While chronographs have been around since the late 1800s, Omega first introduced this line of chronographs in 1957. Since then, many different chronograph movements have been marketed under the Speedmaster name. The manual winding Speedmaster Professional or "Moonwatch" is the best-known and longest-produced; it was worn during the first American spacewalk as part of NASA's Gemini 4 mission and was the first watch worn by an astronaut walking on the Moon during the Apollo 11 mission. The Speedmaster Professional remains one of several watches qualified by NASA for spaceflight and is still the only one so qualified for EVA. The Speedmaster line also includes other models, including analog-digital and automatic mechanical watches.