Powered chairs generally include as a standard feature a manually controlled joystick to regulate the chair’s speed and direction. However, most manufacturers offer customized control options to accommodate the varied abilities of the user, including sip-n-puff systems, head and chin switches, push-button controls, trackballs, and tillers. Many chairs also have programmable control features which allow the user or a dealer to adjust or set the chair’s speed and control limits as the user’s abilities change.