Product review (5 stars): Practical benefits of having the ice melt slower.
The silicone is pretty thick and sturdy, and should last for some time (actually, they should last indefinitely barring an accident such as getting cut with a knife). Using them is very simple  just fill the bottom, put on the top and set in the freezer. If you overfill the excess is caught in the tray. In addition to the practical benefits of having the ice melt slower and provide longer cooling power, it just looks great! Much more attractive than the usual cube.