What is the difference between a lamp and a bare lamp?

Bulb / bare lamp

A bare lamp is a bulb. Bulbs are available for customers if you want to replace the bulb inside by yourself and reuse your existing lamp housing. The main benefit of this option is a considerable price reduction compared to a lamp module. Original projector bulbs come from manufacturers such as Philips, Osram, Ushio, Iwasaki, Phoenix, Panasonic or Matsushita. Your original lamp module will contain a projector bulb made by one of these manufacturers.

Lamp module / lamp

The bulb plus the cage or housing is called a lamp module or lamp; most manufacturers product is supplied as a "lamp module" for quickness and ease of installation.