Bought these as I bought a mini air conditioner and wanted to put ice in with the water to make it extra cool now the warm weather is coming I did have some already but they don't have lids and by the time I have actually got them in the fridge half the water would be missing.
For the first couple of times that I used these I ended tipping more than was left in there, while trying to put the lid on but I soon got the hang of it, gently push the lap of the lid over the edge of the tray until you feel a clicking sensation, don't press the silicone too hard until it's all sealed then it doesn't leak when you carry it to the fridge. Now I am able to use it without any spillage.
Makes good size cubes not large but not small. With 2 trays they make a good few too.
I would happily recommend this product.