Review on Dimmable Standard Industrial Electrical Reflector by HC Lighting: Enhancing Illumination Efficiency by Nick Kussmaul

Lightbulbs will go bad if recklessly broken by tightening a bracket on it, but they work great with normal use. :-) Note: Brightness decreases faster than heating. I used them to charge a lava lamp (40w where 25 should be). It works well, but once you turn it down to 25 it puts out a lot less light than an incandescent bulb designed for that purpose.