Fairy lights technical help, please!

[DrinkFeckArseGirls]

WTF is the thing in the first photo? Thought it was a plug with missing prongs but then found the plug. I emailed the seller but no response yet and no instructions in the box!

Looks like both parts should be joined together?

UK plug adapter I'd presume?

Looks like you could extend with another set maybe?

Its so you can connect more than one set of lights

Ah, I think CrazyMama amd Plump got it. I’d never figure it out

I only know because mine are exactly the same.