There is a multitude of lighting options and it can be confusing understanding what is required. It varies from one trailer to the next and depends on the brand/manufacturer. The first thing to remember are the Legal requirements as detailed below
TRAILER LIGHTING REQUIREMENTS
Offering greater visibility for the driver and others, stalk marker lights come in many shapes and sizes. The main casing is usually made from rubber to prevent breakages and complete loss of the light should anything hit it.