Abstract: A shaft speed signal indicator including a hub, bearing, switch assembly and housing which are mounted as a compact and integral unit to a free end of a revoluble shaft. The signal indicator further includes electric circuitry connected to contacts of the switch assembly for signalling the rotational speed of the revoluble shaft relative to a predetermined revolution rate. The hub carries a plurality of magnets for rotation about a predetermined path and to cause the contacts of the switch assembly to operate at a rate proportional to the movement of the magnets therepast. The housing of the signal indicator maintains the contacts of the switch assembly at a predetermined distance from the magnets and includes an exterior configuration substantially encompassing the hub and shields the end of the revoluble shaft.