Set of 2 track lighting sockets, Kyodo Lighting GT-GD-E26B The base size is E26. I installed them, but the black color didn't match, so I'm listing them here. The socket shape is close to a perfect circle, so it doesn't hit the edge of the track rail and fits in either direction. With the more common shape, like an oval that's been flattened, you can't insert it in the direction where it catches on the edge of the track rail, or it's very difficult to remove if you force it in. However, I think this Kyodo Lighting product avoids that problem. The hinge bend is about 85 degrees. The seller, Kyodo Lighting's website says 90 degrees, but it's actually a little less than 90 degrees. The axis rotation angle is about 315 degrees (7/8 rotation). One of the two sockets is missing the rubber cover for hiding the screw head. Used for less than 10 hours. #See my "Green" IT equipment and electrical products here #See my "Green" interior design related items here #See my "Green" DIY related items here