Product review (4 stars): I've tossed my regular plastic trays
I bought three of these because I got tired of filling ice trays only to refill them too soon.  Two of these cubes in a large glass will last several hours.  I'm only using one tray per day of continuous use, and have thrown away my old regular plastic ice trays.  For a highball glass one is perfect.  They are a little hard to get out of the tray and that is why I didn't give it five stars.  But, the silicone is totally turn-in-side-out-able and I've learned that there's a knack for making them come out easier.  You crack them apart, the push from underneath and if you have to, turn the tray inside out at any cube that is less cooperative.  The silicone is tough and super flexible, even immediately out of the freezer.  The cubes aren't as perfectly square as one could imagine, but that's not the tray's fault, it is how much the ice expands during the freezing process and that is determined by what you are freezing.  I think I read that you can the boil water first for more transparent cubes. They seemed pricey at first but now I see why.  Don't expect them to be firm, they are limp like neoprene (I was surprised by that).  It takes two hands to get them into the freezer without a spill.