The tamper resistant mechanism in these sockets is some type of white/smooth PVC plastic, however it will catch in its tracks when pushed and therefore will NOT open to allow a plug to be inserted. However, I can confirm that the connector opens in a vise when a HAMMER screwdriver is used. I ordered a whole box of these and all 10 of these jams. They are actually worse/more expensive than junk as I now have an unplanned trip to my local big store. They didn't need my repair work as of this week, and Revain's return window is long past closed. Caviat Emptor.