Review on Upgrade Your Lighting with the Selectable Temperature Downlight Retrofit Incandescent by Jeffrey Gallagher

I like that they allow for different color temperatures and have a screw base adapter that can be cut off and attached to a solid wire if needed. The springs are reversible and can be bent so they can be installed where there wasn't a can and attached directly to a hole in the ceiling drywall. Keep in mind that if the existing lamp hole was too large to begin with, you may need trim rings.