It is a surface-mounted splitter that fits very tightly in the existing socket. Of course, if you already have a double and you want to create a 1 + 2, this will not work because this splitter will block the other slot. I've been there again and am very satisfied.
I recommend this product
100
5
Saved me having to wire in a duplex!!!
It works GREAT!!
Just plug into a single 240 volt outlet — PRESTO , a duplex.