Bests & Worsts Reviews from Amazon

I'm an electronic engineer, so to avoid surprises, I tested these items before taking them on a trip. I plugged a 3-prong USA extension cord into each adapter and checked for continuity. All three adapters were fine with the flat blade connections. But the ground (round USA prong) did not make any connection on one adapter and was intermittent on the other two adapters. The location of the ground contacts inside the adapter is marginal for making contact with any 3-prong USA plug. The bottom line is that these adapters would probably work fine for any non-grounded item (e.g., an iPhone A/C adapter) but are unsafe for any usage requiring a ground. It just so happens I also ordered the OREI Grounded Universal 2 in 1 Plug Adapter at the same time. It tested fine and that's what I'll be taking to S. Africa with me.