It's very hot. I want to change to a cooler pillow. I don't know how to choose.

I remember one kind of pillow is inflatable. I feel very sad about it. After all, it is filled with cold water. A cold pillow won't break my head overnight. Right? Then choose the pillow made of bamboo. There are many kinds of pillows, solid and hollow. Choose a hollow one. It will be cold if it is ventilated, that is, ten or twenty dollars.