Got the blue balls... [UPDATED]

... and they are silicon injected :

First try wasn’t great as i overfilled and ended up with one cracked ball (this hurts) :

Second batch went better :

And something that should not be tried at home (don’t worry, the pepper grinder is just here for artistic purpose) : Whisky & Boga “Cidre” with lime, not to mention the cracked ball from the first batch...

I really recommend it, for around 2.5€ each including shipping it’s a great thing to have.

Bought it here but the price has doubled since (but there are still some other sellers that sells them for less).

UPDATE : New batch !

I was going to go to bed but the comments forced me to check my 3rd batch that i did put this evening.

This time, i did a ballsy move by using hot water as it is supposed to freeze faster than cold water but the result isn’t great (they look like the Death Star) :

Then i turned around some :

To be honest i don’t care much that they don’t look perfect but next time i will try the other way around (as proposed by pyroholtz) by putting them on the fridge before the freezer so the temperature drop will be less violent and there might be less bubbles trapped inside.