Product review (5 stars): Nice!
I have a few ice ball molds, and this is my favorite set.

A little warm water and they unmold more easily than silicone molds. They also stack well in the freezer. The balls are nicely sized, and look very nice in a rocks glass. The fill lines show you how far to fill it to account for expansion. They also clean easily which is great if you want to use something other than water in the molds.

Using boiled water makes a clearer ice, but generally my family just uses plain water in them which creates some gorgeous effects in the ice.
[The product reviewed was provided to me at no cost for the purposes of review. I received no other compensation, and my review is my honest opinion of the product.]