I am not sure why you would need that or how you keep the 240v plugs out.
Yah, it makes me wonder why they are still making something like that.[with the tandem slots] What is the use? 240 plugs? New ones have a grounding prong. You'll either need a side cutter or a hammer to make that fit... I don't think I have seen an old 2 prong tandem plug for sale. I have seen some old 2 prong plugs with one blade tandem and the other straight, and it was rated 15 A 125 V. It wasn't terribly old either.I wonder if this receptacle is dual rated like the old ones were, something like 15 A 125 V and 10 A 250 V. Note: Non UL. it says. Perhaps it is manufactured for other countries such as Mexico or some South American countries that do not have listing requirements?
I seen this pic posted on another board, and thought (Or hoped) someone photoshopped it...