Early turret clocks seldom had dials, and indicated the passage of time by striking the hours on a bell. When dials were fitted, the hands were connected to the clock by rods; the gears and rods to the dial (or dials) are known as leading-off work. In the 18th century the leading-off work was fitted with a friction clutch and a setting dial. These features made it possible to set the clock to time without having to 'pump' the escapement or stop it.