This is a 7" school bus tail light full assembly. It is definitely not vintage, but if you have a late 1950s to 1970s travel trailer that does not have taillights and you need something that is the same diameter as the taillights of that era, this is a functional replacement that will give you stop/turn/tail functions.

If you have vintage Auto-Lamp 575 lenses, these are very similar diameter but the base is not compatible with the old lenses.

The base surface mounts to your trailer with four screws on a 6.25" bolt circle.

It has one incandescent two-function 1157 bulb.  There are three wires coming out of the back.

• The red wire goes to the brighter filament.
• The black wire goes to the dimmer filament. 
• The white wire is common ground.

The red acrylic lens attaches to the lamp base with 4 screws It requires a 1" diameter hole 1" deep in the center for the bulb socket and pigtail.

The heavy duty steel base is painted with black epoxy for rust prevention.