LEVEL. THE BALL IN ITS RELEASED CONDITION, CAUSES A RATTLING OR OTHER AUDIBLE SIGNAL TO PROVIDE WARNING TO THE VEHICLE OPERATOR IF THE CONDITION OCCURS WHILE THE VEHICLE IS MOVING.

A DEVICE RESPONSIVE TO FLUID PRESSURE FOR DETECTING AND INDICATING VISUALLY AND ACOUSTICALLY THE PRESENCE OF AN UNACCEPTABLE PRESSURE CONDITION SUCH AS THE UNDERINFLATION OF AN AUTOMOBILE TIRE. THE DEVICE WHEN USED ON AN AUTOMOBILE WHEEL IS SYMMETRICAL ABOUT THE AXIS OF THE WHEEL TO ASSURE PROPER WHEEL BALANCE. A PERMANENT MAGNET IS MOVED IN RESPONSE TO FLUID PRESSURE IN SUCH A WAY THAT WHEN AN UNACCEPTABLE PRESSURE CONDITION IS SENSED, A STEEL INDICATOR BALL IS RELEASED FROM A NORMAL VISIBLE POSITION TO PROVIDE N INDICATION OF N UNSAFE TIRE INFLATION