What is "dualshock"

The DualShock (originally Dual Shock; trademarked as DUALSHOCK or DUAL SHOCK) is a line of gamepads with vibration-feedback developed by Sony Interactive Entertainment for PlayStation consoles and devices. The DualShock was introduced in Japan in late 1997 and was launched in the North American market in May 1998. First introduced as a secondary peripheral for the original PlayStation, an updated version of the PlayStation console included the controller. Sony subsequently phased out the digital controller that was originally included with the console, as well as the Sony Dual Analog Controller. , over 28 million DualShock controllers have been sold under the brand's name, excluding bundled controllers.