What is the difference between a shielded and a non-shielded halogen bulb? Yeah, bob, I know, the shield, but what IS that shield? And why does it increase the cost of the bulb x6? My hood range takes shielded halogen bulbs, and they cost $30. We have the bulb at work, but it's not shielded, and it costs $5. I will still pay the difference for the shielded bulb, but what the heck is it and what does it do?