Review on Legrand Pass Seymour 128ICC10 Lampholder Applications by Darth Naubert

Used to connect two bulbs to the same socket when you need more light. Works as expected. I wish it had a spring tab at the bottom of the socket instead of a solid contact plate. It will not screw under a regular lamp harp, so the harp must be removed to install it (you can put the harp back in after it's screwed in). Make sure your bulbs are a few inches from the lampshade to avoid fire when using them in a lamp.