It's a vintage curling iron with an ingenious idea - this curling iron has 3 different interchangeable sizes. Here's another pic of the backside of the box:
So, basically, you have a 3/4", 5/8" and 1/2" curling iron all-in-one. I think that is a pretty savvy idea, don't you? I have never heard of the "Curl Master" curling iron prior to my sister-in-law and my discovery. Have you ever heard of it?
Here is another pic of the actual curling iron: