Review on eDragon Polarized 3 Prong to 2 Prong Grounding Converter for AC Outlet, 5 Pack (ED71583): Enhance Safety and Compatibility in Your Electrical System by Jamie Sorenson

Looks ok but I haven't even used them yet. I have based my purchase on two replies I have received from other customers saying the forks are identical in size at the ends which is what I needed. They are polarized and have one tooth larger than the other. I have a device with a female end with equal sized holes (small) that is used for Christmas lights. The new Christmas lights are polarized so they won't work in my device. If you buy for the same reason they will NOT work. They will NOT allow you to connect new flashlights with a wider/bigger/thicker pin back to back with older lights with the same pin.