The Rotary Beacon No. 394 used the heat from the light bulb to rotate the beacon. It used a special dimpled bulb to center the pin of the beacon head assembly. Available from 1949 until 1953, there are two wire clips on the bottom to connect this accessory to a power source. In 1954 this beacon would be replaced by the No. 494.

Since this accessory used heat from the lamp to work, it is advisable that an accessory circuit, that is always on, should be used to run this beacon. This is to keep the lamp hot so that the beacon will continue to rotate.

There are six variations of this Rotary Beacon:

Variation A: has a RED painted stamped steel tower with a SERIF lettering on the plate.

Variation B: same as A except has SANS-SERIF lettering on the plate.

Variation C: DARK GREEN painted stamped steel tower.

Variation D: unpainted Aluminum tower.

Variation E: same as C except that it has an aluminized sticker instead of a plate.

Variation F: same as C but has a RED painted base.

All of the painted variations of this beacon are more difficult to find.

Dimensions: 11-3/4 inches high, with a 5 inches square base.