Darley beacons were a mainstay for small towns and rural areas. They were simple, inexpensive and durable. A number of them are still in service today although many of the ones still in service have been modified to have separate illumination for each indication.

Darley beacons came in three models.

• An all amber (yellow) beacon was a D-130.
• A combination amber / red beacon was a D-131.
• An all red beacon was a D-132.

The original beacon design included a Reynolds Time-O-Matic flash controller and lamp socket on the beacon floor. The lamp, usually 150 watts, illuminated all four indications. Reflectors attached to the lenses amplified the light and reduced phantom illumination.